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SPECIMEN  OF  THREE-COLOR  WORK. 


Engraved  and  printed  by  the  Chicago  Colortype  Company,  120^-1215  Roscoe  St.,  Chicago 


A    MANUAL 


PHOTO-ENGRAVING 


CONTAINING   PRACTICAL   INSTRUCTIONS 
FOR   PRODUCING 


PHOTO -ENGRAVED    PLATES 


RELIEF -LINE  AND   HALF-TONE 

WITH 

CHAPTERS    ON    DRY    PLATE    DEVELOPMENT    AND 
HALF-TONE    COLOR    WORK. 


By  H.  JENKINS. 


CHICAGO  : 

The  Inland  Printer  Company, 

1896. 


Copyright,  1896, 

BY 

The  Inland  Printer  Company, 
Chicago,  Illinois. 


Press  of 

The  Henry'  O.  Shepard  Co,: 

Chicago. 


THEGfm    ;i   .  lk 
LIBRARY 


PREFACE. 


IN  preparing-  this  work,  it  has  been  my  aim  to 
present  such  information  that  a  person  inex- 
perienced in  photographic  operations  might  be 
enabled  to  obtain  from  it  an  intelligent  conception 
of  the  methods  used  for  making  line  and  half-tone 
engravings. 

If  therefore  details  have  been  entered  into  which 
may  to  some  seem  superfluous,  it  should  be  remem- 
bered that  what  may  appear  self-evident  to  the 
expert  may  often  be  perplexing  to  the  novice  unless 
clearly  explained. 

While  entering  thus  into  detail  regarding  the 
processes  treated  of,  I  have  avoided  the  discussion 
of  obsolete  and  untried  methods,  and  have  endeav- 
ored to  make  the  descriptions  as  brief  as  possible 
without  sacrificing  clearness. 

The  methods  described  are  those  used  in  the  reg- 
ular engraving  establishments,  and  I  believe  that 
with  careful  study  and  properly  directed  effort,  the 
beginner  will  obtain  satisfactory  results. 

(3) 


4  PREFACE. 

In  addition  to  the  chapters  devoted  to  the 
engraving-  processes  I  have  prepared  a  chapter  on 
the  development  of  the  gelatine  dry  plate,  as  a  work 
of  this  nature  would  seem  incomplete  without  some 
information  on  that  subject. 

The  excellent  photographs  from  which  a  num- 
ber of  the  half-tone  plates  were  made  were  the 
work  of  Mr.  A.  C.  Pack,  of  the  Randall  studio, 
Ann  Arbor. 

H.    JENKINS. 

Chicago,   October    1,    1896. 


CONTENTS. 


PAGE 

Chapter  I.     Introductory 7 

Chapter  II.     The  Apparatus  Required 9 

Chapter  III.     The  Shop  Arrangement 23 

Chapter  IV.     Negative  Making  29 

General  Principles  —  Chemicals. 

Chapter  V.     Negative  Making 39 

Line  Negatives. 

Chapter  VI.     Negative  Making 49 

Half-tone  Negatives. 

Chapter  VII.     Negative  Making 62 

Causes  of   Defects   in   Collodion  Negatives  —  Care 
of  Silver  Bath. 

Chapter  VIII.     Reversing  Negatives 66 

Chapter  IX.     Etching 69 

Line  Work. 

Chapter  X.     Etching 81 

Half-tone  Work  —  The  Enamel  Process. 

Chapter  XI.     Finishing  and  Mounting  Plates 87 

(5) 


b  CONTENTS. 

PAGE 

Chapter  XII.     Drawings  —  Photo-Lithogravure  . . .     90 

Chapter  XIII.     Development  of  Gelatine  Dry 

Plates , 96 

Chapter  XIV.     Orthochromatic  Plates 105 

Color  Work. 

Chapter  XV.     Printing  Half-tone  Plates ...  114 

Appendix.     Tables  of  Weights  and  Measures 122 

Valuable  Formula;  —  Printing  Methods  —  Etched 
Embossing-  Plates  —  Other  Useful  Informa- 
tion. 


MANUAL  OF  PHOTO-ENGRAVING. 


CHAPTER  I. 
INTRODUCTORY; 

A  COMPARISON  of  the  periodicals  of  several 
years  ago  and  those  published  today  reveals 
to  the  observer  a  marked  difference  in  the  number 
and  quality  of  the  illustrations.  In  the  former  we 
find  but  few  cuts,  and  those  engraved  on  wood, 
often  in  an  indifferent  manner.  In  the  magazines 
and  newspapers  of  the  present,  however,  nearly 
every  page  exhibits  one  or  more  illustrations  of 
most  artistic    character. 

While  wood  cuts  are  still  used  to  a  considerable 
extent  for  general  illustrative  purposes,  the  major- 
ity of  the  engravings  are  at  present  produced  by 
the  now  well-known  processes  of  engraving  by  aid 
of  photography.  The  several  advantages  which 
photo-engraving  possesses  over  wood  engraving 
have  created  a  demand  which  has  steadily  increased 
and  opened  avenues  of  employment  to  many  who 
have  taken  up  this  branch  of  work  as  a  profession. 
A  cut  which  formerly  would  have  required  several 
days  to  produce  can  now  be  turned  out  in  a  few 

(7) 


o  MANUAL   OF    PHOTO-ENGKAVING. 

hours,  and  will  have  reproduced  all  of  the  features 
of  the  original  copy  to  exactness,  while  its  cost  is 
but  a  fraction  of  that  for  wood  engraving". 

While  there  are  several  methods  of  engraving 
which  depend  upon  photography  for  their  existence, 
the  term  "photo-engraving"  is  usually  applied  only 
to  relief  plates  in  line  and  half-tone,  and  to  a  de- 
scription of  this  class  of  work  the  following  pages 
will  be  devoted. 

To  the  inexperienced,  photography  often  seems 
to  be  a  mysterious  and  difficult  art,  but  the  manip- 
ulations described  hereafter  will  with  proper  study 
become  remarkably  simple  when  the  results  attain- 
able are  considered. 

The  production  of  a  photo-engraved  plate  in- 
cludes several  stages  as  follows : 

1.  The  making  of  a  negative. 

2.  The  printing  of  the  image  on  the  metal. 

3.  The  etching. 

4.  The  finishing  and  blocking. 

In  regular  establishments  separate  departments 
are  devoted  to  each  branch,  every  employe  being  a 
specialist  in  his  line. 

A  description  of  the  details  which  are  included 
in  each  of  the  various  stages  will,  however,  be  given, 
that  the  reader  may  obtain  a  general  knowledge 
of  the  art. 


HALF-TONE—  150-LINE    SCREEN. 


MANUAL   OF    PHOTO-ENGRAVING. 


CHAPTER   II. 

THE   APPARATUS   REQUIRED. 

THE  apparatus  required  for  making-  photo- 
engravings will  vary  in  completeness  with 
the  amount  and  quality  of  work  to  be  turned  out. 
For  the  experimenter  or  the  establishment  which 
devotes  but  a  small  department  to  the  work,  an 
equipment  of  hig-h  grade  and  larg-e  capacity  would 
be  out  of  the  question.  For  larg-e  shops,  however, 
which  are  established  with  a  view  to  commanding-  a 
large  patronage,  where  rapidity  of  production  and 
a  uniformly  excellent  quality  of  work  are  impor- 
tant matters  of  consideration,  it  is  essential  that 
the  apparatus  be  of  the  most  approved  pattern, 
and  that  each  department  be  fully  equipped. 

The  capacity  of  the  apparatus  should  be  deter- 
mined by  the  size  of  plates  demanded.  The  aver- 
age engraving-  establishment  will  find  an  equipment 
for  producing-  plates  14  by  17  inches  in  dimensions 
ample.  The  demand  for  half-tone  plates  is  usually 
for  sizes  under  10  by  12  inches,  and  many  shops 
are  not  provided  with  facilities  for  plates  larg-er 
than  that  size.  Line  plates  are  also,  as  a  rule,  of 
dimensions  smaller  than  this,  but  provision  should 
be  made  for  work  of  as  larg-e  dimensions  as  the 
funds  available  will  permit,  and  the  prospective 
order  may  require. 


10  MANUAL   OF    PHOTO-ENGRAVING. 

The  article  of  the  greatest  importance,  in  con- 
nection with  the  outfit,  is 

THE    LENS. 

This  should  be  selected  with  a  view  to  its  fulfill- 
ing- the  special  requirements  of  this  class  of  work. 
It  should  be  of  the  rectilinear  type,  so  that  all 
straight  lines  in  the  copy  will  be  reproduced  with- 
out distortion.  It  should  cut  clearly  all  portions  of 
the  copy,  and  its  design  should  be  such  that  it  may 
possess  rapidity.  There  are  several  lenses  on  the 
market  which  fulfill  these  requirements — the  Rapid 
Rectilinear  Dallmeyer,  the  Steinheil  and  Swift 
being  popular  among  operators. 

THE    CAMERA. 

In  selecting  the  camera  it  is  advisable  to  obtain 
the  form  known  as  the  enlarging,  copying  and 
reducing  camera,  as  its  construction  possesses  sev- 
eral advantages  over  the  ordinary  copying  camera. 

For  half-tone  work  it  should  be  provided  with 
the  adjustable  screen  plateholder,  which  enables 
the  kit  to  be  dispensed  with  for  holding  the  screen 
and  sensitive  plate.  It  is  so  constructed  that  the 
separation  of  screen  and  plate  can  be  adjusted 
accurately  and  easily  to  any  desired  degree,  and 
different  sizes  of  screen  and  plates  can  be  used. 

This  plateholder  has  displaced  the  kit  in  all 
leading  shops,  but  for  those  who  may  desire  to 
use  the  kit,  details  of  construction  will  be  given 
further  on. 


MANUAL   OF    PHOTO-ENGRAVING. 


11 


CAMERA    STAND. 

The  camera  should  be  provided  with  a  stand, 
which  may  be  in  the  form  of  a  long-  table  or  bench 
to  stand  on  the  floor,  or  it  may  be  swung-  from  the 
ceiling-,  this  condition  being  necessary  if  the  build- 
ing is  subject  to  vibrations  from  the  running*  of 
machinery  or  other  causes.  It  consists  essentially 
of   an  oblong-  frame  upon  which    the  camera  will 


CAMERA   AND   SWING 


slide  readily,  the  frame  being  suspended  from  a 
beam  of  the  same  leng-th,  ropes  or  strips  of  metal 
running-  from  the  ends  of  the  beam  and  attached  to 
each  end  of  the  frame  in  an  inverted  V  shape. 
The  beam  being  suspended  from  the  ceiling-,  carries 
the  frame  upon  which  the  camera  is  placed.  At 
one  end  of  the  frame  the  copy  board  is  fastened, 
and  should  be  in  a  position  perpendicular  to  the 
bed,  and  should  be  arranged  to  slide  from  ri^ht  to 


12  MANUAL    OF    PHOTO-ENGRAVING. 

left  when  desired.  The  length  of  bed  will  vary 
according-  to  the  capacity  of  the  camera.  For  a 
10  by  12  camera,  ten  feet;  11  by  14,  twelve  feet; 
and  for  a  14  by  17  camera  fourteen  feet  are  good 
proportions.  Such  a  bed  can  be  easily  constructed 
of  ordinary  scantling,  or  can  be  purchased  from 
dealers  in  photo-engravers1  supplies. 

SILVER    BATH. 

The  silver  bath  is  almost  invariably  kept  in  a 
glass  vessel  of  special   form,  which,  when  holding 

the  bath  for  use,  should 
be  kept  in  a  ''light- 
tight  "  box,  with  a  cover. 
It  is  important  that  a 
bath  of  ample  capacity 
be  provided,  as  such  a 
one  will  require  less  at- 
tention than  a  small  one 
and  save  the  operator  an- 
noying delays.  In  all 
well  equipped  shops   two 

SILVER    BATH.  01"       m0re       batllS       ^       P1"0" 

vided  for  each  operator, 
that  one  may  be  used  while  another  is  being 
rectified. 

EVAPORATING    DISH. 

For  evaporating  the  alcohol  from  the  bath,  a 
porcelain  evaporating  dish  is  required.  It  should 
be  of  ample  capacity  to  hold  the  silver  solution  from 
the  bath,  with  room  to  spare.     As  an  accessory,  it 


MANUAL   OF    PHOTO-ENGRAVING. 


13 


is  well  to  have  an  iron  dish  to  hold  sand  in  which 
the  porcelain  dish  can  rest  while  heating-. 

TRAYS. 

For  line  etching-  there  should  be  one  or  more 
large  trays  or  "tubs"  so  arranged  that  they  may 
rock   at   the  will  of   the  etcher.     These  tubs  are 


made  of  wood,  sealed  water-tight  and  usually  pro- 
tected by  a  coating  of  impermeable  varnish.  For 
developing  prints  on  zinc,  any  ordinary  sheet  metal 
tray  will  serve  the  pur- 
pose. For  half-tone 
etching  porcelain  or  rub- 
ber  trays  may   be  used. 

PRINTING    FRAMES. 

For  printing  on 
metal  there  are  special 
frames,  so  constructed 
that  equal  contact  with 
the  negatives  can  be  obtained  for  all  parts  of  the 
metal  plates.  For  making  silver  prints  the  ordi- 
nary photographer's  printing  frame  is  used. 

GLASSWARE. 

For  measuring  solutions,  several  graduates  of 
a   capacity  of    from  eight  to  sixteen  ounces  each 


PRINTING    FRAME. 


14 


MANUAL   OF    PHOTOENGRAVING. 


should  be  purchased.  There  should  also  be  a  large 
funnel  for  filtering-  the  baths  and  several  smaller 
ones  for  collodion,  printing 
solutions,  etc. 

An  important  article  is  the 
actino-hydrometer  for  testing 
the  strength  of  the  silver 
bath. 

Various  sizes  of  plate 
glass,  as  required,  should  be 
provided  for  negative  making 
and  for  turning  negatives 
upon.  For  the  latter  purpose 
the  glass  is  usually  obtained 
of  one-fourth  inch  in  thick- 
ness, to  more  readily  stand  the  pressure  in  the 
printing  frame. 

Vials  for  hold- 
ing collodion, 
large  bottles  for 
filtering  the  bath 
into,  and  smaller 
ones  for  solutions 
are  also  necessi- 
ties. 

ROLLERS. 

For  inking  line 
plates,  composi- 
tion rollers  are 
used.  These 
should  be  of  the  kind  known  as  "hard"  rollers, 
as  they  more  readily  take  and  distribute  the  ink. 


GRADUATE. 


COLLODION   VIAL. 


MANUAL    OF    PHOTO-ENGRAVING. 


15 


An  excellent  roller  for  this  purpose  can  also  be 
made  from  white  rubber,  such  as  is  used  for  clothes 
wringers.  For  inking-  the  plate  after  etching-,  a 
leather-covered  roller  is  usually  used. 


MISCELLANEOUS    ARTICLES. 

Besides  the  articles  described  above,  there  are 
other  essentials,  as  follows  :  Gas  stoves,  for  heating 
and  drying-  plates  ;  squeeg-ees,  for  smoothing-  down 
neg-ative  films  —  these  are  simply  strips  of  white 
rubber  fastened  to  a  strip  of  wood  ;  scales,  for 
weighing-  dry  chem- 
icals ;  negative  racks  ; 
brushes  for  etching-  — 
bristle  for  line  etch- 
ing-, and  soft  for  half- 
tone ;  inking-  slab  for 
rolling  ink  upon  —  a 
smooth  sheet  of  stone, 
zinc  or  glass  will  an- 
swer the  purpose  ;  pli- 
ers, for  holding  plates 
while  burning  in  ;  zinc  hook,  for  cutting  zinc  plates  ; 
small  camel's-hair  brushes,  for  spotting  and  paint- 
ing in  on  plates  ;  egg  beater  ;  hammers  ;  nails  ; 
scraping  tools,  for  cleaning  spaces  on  zinc  ;  engrav- 
ers' tools,  for  tooling  plates  after  etching  ;  files,  for 
smoothing  edges  of  metal ;    calipers,  punches,  etc. 

MACHINERY    FOR    FINISHING. 

For   a    well    equipped    shop    there    are    several 
machines  which  are  essential.     Small  concerns  are 


NEGATIVE    RACK. 


16  MANUAL   OF   PHOTO-ENGRAVING. 

often  operated  with  but  a  small  equipment  of 
machinery,  but  for  large  establishments  the  outfit 
of  necessary  machinery  is  in  many  cases  a  very 
extensive  affair. 

The  routing-  machine  is  the  most  important  item 
in  this  department,  and  is  used  for  deepening-  and 
cleaning  out  the  spaces  in  zinc  etchings,  making  a 
bevel  around  half-tones,  etc.  These  machines  can 
be  obtained  in  various  sizes  according  to  the  dimen- 
sions of  plates  to  be  routed. 

A  circular  saw  is  also  an  essential  piece  of 
machinery,    for    sawing   metal    plates,  blocks,  etc. 

The  trimmer,  as  its  name  indicates,  is  used  for 
trimming  the  edges  of  blocks  after  the  plates  are 
mounted. 

The  shoot  board  is  used  for  a  similar  purpose 
and  is  generally  substituted  for  trimmer  in  small 
shops. 

The  Daniel's  planer  is  used  for  making  mounted 
blocks  type-high.  It  is  an  expensive  machine,  and 
for  small  establishments  the  shaving  machine  oper- 
ated by  hand  can  be  used  instead. 

A  drill  is  often  of  use  for  various  purposes,  and 
is  necessary  in  mounting  half-tone  plates  from  the 
back. 

The  beveling  machine  is  used  for  beveling  the 
edges  of  plates. 

The  buffing-  machine  is  used  for  polishing  metal. 
It  is  not  found,  as  a  rule,  in  small  shops,  as  the 
metal  can  be  polished  by  hand. 

For  taking  proofs,  a  printing  press  is  required, 
and  for  the  engraving  establishment  the  hand  press 


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ZINC    ETCHING  — CRAYON     EFFECT. 
From  sketch  by  Frank  Holme. 


MANUAL   OF    PHOTO-ENGRAVING.  IT 

known  as  the  "Franklin"  or  "Washing-ton"  type 
is  best. 

The  mounting-  slab  is  simply  a  smooth-surfaced 
block  of  iron  upon  which  the  cuts  are  placed  when 
being  blocked. 

A  detailed  description  of  the  above  mentioned 
machinery  is  not  given  here,  on  account  of  the 
various  designs  on  the  market,  and  as  manufac- 
turers are  always  ready  to  send  to  inquirers 
descriptions  of  all  latest  improvements. 

THE    WHIRLEK. 

In  coating  plates  for  half-tones  with  the  enamel 
solution  it  is  necessary,  in  order  to  obtain  an  even 
coating,  that  a  rapid  whirling  motion  be  given 
while  the  solution  is  in  the  fluid  condition  on  the 
plate. 

A  number  of  devices  can  be  used  for  this  pur- 
pose. A  common  form,  sold  by  the  supply  houses, 
consists  of  a  handwheel  mounted  in  a  horizontal 
position  on  a  board  and  connected  by  means  of  a 
belt  with  a  table  similarly  mounted  at  the  other 
end  of  the  board,  the  table  being  provided  with 
clamps  to  fasten  the  plate.  Upon  revolving  the 
handwheel  the  table  is  caused  to  revolve  also,  thus 
spreading  the  solution  in  an  even  coating  over  the 
plate. 

A  much  better  whirler,  however,  can  be  con- 
structed by  means  of  an  ordinary  drill  stock,  as 
follows :  To  the  bottom  of  a  shelf  placed  at  a 
convenient  height  fasten  the  drill  stock  as  shown 
in    Fig.   A.      Then    at    a    machine    shop   obtain    a 


18 


MANUAL    OF    PHOTOENGRAVING. 


strip  of  iron  about  three-fourths  of  an  inch  or  an 
inch  in  width,  one-sixteenth  of  an  inch  in  thick- 
ness, and  twelve  or  fifteen  inches  long-,  and  to  its 
center  have  fastened  a  round  stem.  Fig.  B.  Also 
have  made   two   strips   about   four   or  five  inches 


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»-u 


C 


J 5. 


WHIRLER. 


long-  with  apertures  cut  at  each  end,  those  at  one 
end  of  a  size  and  shape  to  admit  the  ends  of  the 
other  strips.  Have  one  of  the  ends  of  each  of 
the  latter  strips  bent  over,  and  a  hole  drilled  to 
admit  a  thumbscrew,  as  shown  in  the  cut,  Fig.  C. 
The  long  strip  is  fastened  in  the  chuck  of  the 
drill  by  means  of  the  stem  and  the  two  short  strips 
are  slipped  over  the  ends,  as  shown  in  Fig.  C.  A 
gas  stove  should  be  placed  under  the  whirler  to 
warm  the  plate  and  accelerate  the  drying  of  the 
coating. 


MANUAL   OF    PHOTO-ENGRAVING. 


19 


The  use  of  this  whirler  will  be  explained  in 
a  later  chapter. 

THE    KIT. 

Before  the  advent  of  the  plateholder  mentioned 
in  a  preceding-  paragraph,  the  kit  was  used  by 
operators  to  hold  the  screen  and  sensitized  plate 
during  exposure,  and  is  yet  used  by  those  who  do 
not  wish  to  incur  the  extra  expense  of  the  holder. 


IL.fl 


r                                                       ' 

c 

'                                                      ; 

The  kit  is  simply  a  rectangular  frame  so  con- 
structed that  when  placed  in  the  plateholder  of  the 


20  MANUAL    OF    PHOTO-ENGRAVING. 

camera  the  negative  plate  will  occupy  the  position 
of  the  ground  glass  and  the  screen  be  held  in  front 
of  it.  Its  construction  can  be  understood  by  an  ex- 
amination of  the  illustration.  A  is  a  frame  made 
of  strips  of  cherry,  walnut  or  other  suitable  wood, 
about  one  inch  wide,  one-eighth  inch  thick  and  of 
lengths  required  by  the  size  of  screen.  The  ends 
should  be  mortised  and  glued  strongly  together. 
On  the  opposite  side  of  this  frame  is  fastened  a 
second  frame  of  strips,  one-half  inch  wide  and  one- 
fourth  inch  thick,  and  so  placed  that  the  inner 
edges  of  this  frame  will  be  flush  with  the  inner 
edges  of  the  other.  The  ends  of  this  second  frame 
should  be  fastened  in  a  similar  manner  to  those  of 
the  first.  To  the  longest  sides  of  this  second 
frame  should  be  fastened  springs,  which  may  con- 
sist simply  of  elastic  curved  strips  of  brass  or 
steel,  the  springs  being  fastened  at  one  end  so  that 
they  can  be  moved  so  as  to  allow  the  other  end  to 
press  upon  the  screen  when  in  position.  These 
sides  of  the  second  frame  should  be  thin  in  the  cen- 
ter so  that  the  springs  will  not  interfere  with  the 
slide.  Across  the  corners  of  the  kit  between  the 
frames  of  which  it  is  composed  are  placed  four  cor- 
ner pieces  to  separate  screen  and  plate.  These  are 
often  of  silver  but  may  also  be  made  of  wood,  and 
should  be  no  thicker  than  to  prevent  contact  of 
screen  and  plate,  and  should  be  set  into  the  first 
frame  so  as  to  be  flush  with  the  side  next  the 
second  frame. 

In  the  diagram,  A  represents  the  first  frame  ; 
B,  the  second,  with  a  view  of  one  edge  of  the  sides 


HALF-TONE— 120-LINE    SCREEN. 


.MANUAL   OF    PHOTO-ENGRAVING.  -1 

containing-  the  springs  ;  C,  the  kit  complete,  with 
corners. 

The  kit  should  be  made  of  a  size  to  readily 
admit  the  screen  used,  negative  glass  of  the  same 
size  being  used  also.  It  should  be  thoroughly  cov- 
ered with  shellac  varnish,  to  prevent  the  silver 
destroying  the  wood. 

The  use  of  the  kit  will  be  explained  in  the  chap- 
ter on  half-tone  negative  making. 

THE   SCREEN    PLATE. 

The  screen  plate  is,  of  course,  absolutely  nec- 
essary in  half-tone  negative  making.  The  size 
obtained  should  be  governed  by  the  size  of  the 
half-tone  plates  which  the  establishment  expects 
to  make. 

The  description  of  the  screen  and  its  uses  will 
also  be  given  in  a  later  chapter. 

CHEMICALS. 

The  chemicals  required  for  making  the  collo- 
dion negatives  and  for  the  etching  operations  are 
as  follows : 

Alcohol  (grain).  Iron  sulphate  (ferrous). 

Alcohol  (wood).  Iron  perchloride. 

Ether  (sulphuric).  Potassium  permanganate. 

Gun  cotton.  Iodine. 

Ammonium  iodide.  Silver  nitrate. 

Cadmium  iodide.  Turpentine. 

Potassium  iodide.  Ammonia  (strong). 

Potassium  bromide.  Castor  oil. 

Potassium  cyanide  (fused)  Ammonium  sulphide. 

Ammonium  bichromate.  Eosine. 

Strontium  chloride.  Le  Page's  liquid  glue. 


22  MANUAL    OF    PHOTO-ENGRAVING. 

Calcium  chloride.  Rubber  cement. 

Mercuric  chloride.  Transfer  etching  ink. 

Ammonium  chloride.  Lye. 

Acetic  acid.  Dragon's  blood. 

Nitric  acid  (Com.).  Sodium  bicarbonate. 

Nitric  acid  (C.  P.).  Absorbent  cotton. 

Chromic  acid.  Charcoal  blocks. 
Copper  sulphate. 

Ordinary  charcoal  will  not  answer  the  purpose 
of  polishing-  the  metal.  The  most  suitable  is  that 
used  by  jewelers  for  soldering-  purposes  and  is 
obtained  in  blocks  of  about  3  by  4  inches. 

To  insure  success  most  of  the  chemicals  men- 
tioned above  should  be  chemically  pure.  They 
should  be  kept  in  bottles  corked  or  stoppered  to 
prevent  evaporation  or  deterioration.  The  bottles 
should  be  plainly  labeled  to  prevent  errors  when 
the  contents  are  wanted  for  use. 


MANUAL   OF    PHOTO-ENGRAVING. 


23 


CHAPTER   III. 
SHOP  ARRANGEMENT. 

IT  is  a  difficult  matter  to  prescribe  a  set  plan  for 
the  arrangement  of  a  photo-engraving-  estab- 
lishment, as  there  is  such  great  variation  in  the 
size  and  relative  positions  of  rooms  which  may  be 
selected  for  occupation,  and  as  large  shops  require 
more  extensive  accommodations  and  special  features 
which  need  not  enter  into  the  equipment  of  smaller 
concerns. 

There  are  general  principles,    however,    which 
can   be   applied   in    fitting  up   any  shop,   and    the 


a  s   a 


nu 


a 


i] 


SHOP    ARRANGEMENT. 


accompanying   diagram   is  given   to   represent   an 
arrangement  for  a  shop  of  moderate  size. 


24  MANUAL   OF   PHOTO-ENGRAVING. 

THE   OPERATING   ROOMS. 

A  is  the  room  for  the  half-tone,  and  B  for  the 
line  operating-.  One  room  is  often  used  for  two  or 
more  cameras,  but  it  is  advisable,  if  possible,  to 
provide  separate  apartments  for  the  cameras,  thus 
avoiding-  interference  of  one  operator  with  another. 
1  and  4  are  the  darkrooms.  These  may  be  con- 
structed with  walls  of  ordinary  flooring  joined  to 
be  light-tight.  They  should  contain  sinks  3  and  5, 
over  each  of  which  should  be  placed  a  tap  for  wash- 
ing the  negatives.  At  the  right  of  the  sink  there 
should  be  placed  a  shelf  for  holding  the  bottles  of 
developer  and  other  solutions.  Other  shelves 
should  also  be  provided  for  holding  stock  solutions, 
and  other  accessories.  Above  the  sink  there  should 
be  a  window  containing  a  light  of  orange  glass, 
and  arranged  to  slide  open  readily  at  the  will  of 
the  operator.  If  dry  plates  are  to  be  developed, 
arrangement  should  be  made  to  close  up  the  yellow 
light  and  substitute  the  ruby  light  required  for 
dry-plate  work. 

The  silver  bath  should  be  placed  in  a  receptacle 
at  the  back  of  the  darkroom,  the  bath  holders 
being  placed  at  such  a  level  as  to  permit  the  con- 
venient lowering  of  the  plate  into  it.  Above,  or 
at  one  side  of  the  silver  baths,  a  shelf  should  be 
located  upon  which  the  plateholder  can  rest. 

The  darkroom  should  be  of  dimensions  large 
enough  to  give  ample  room,  and  should  be  free  from 
cracks  and  openings  through  which  light  might 
pass.  2  and  6  are  benches  for  holding  negative 
racks  and  other  articles. 


VIGNETTED     HALF-TONE  —  i  75-LINE    SCREEN. 
From  wash  drawing-  by  C.  W.  Traver. 


MANUAL   OF   PHOTO-ENGRAVING.  25 

The  location  of  the  cameras  should  be  such  as 
to  be  convenient  to  the  darkroom,  and  they  should 
be  swung-  at  a  height  to  be  most  convenient  for  the 
operator  to  manipulate. 

The  illumination  of  the  copy  is  an  important 
factor  in  producing-  negatives,  and  provision  should 
be  made  for  obtaining  the  best  facilities.  The 
light  can  be  obtained  either  from  a  skylight,  or  by 
means  of  electric  lamps.  In  many  shops  both 
means  are  provided,  the  light  being  obtained  from 
the  skylight  during  the  bright  hours  of  the  day, 
and  from  the  lamps  at  other  times.  The  skylight 
should  be  as  large  as  convenient,  to  furnish  an 
ample  volume  of  light.  The  lamps  should  be  arc 
lamps,  and  should  be  swung,  one  on  each  side  of 
the  camera  stand,  near  the  copy  board,  in  such  a 
manner  that  they  may  be  readily  raised  or  lowered. 
They  may,  if  desired,  be  arranged  with  movable 
stands,  instead  of  being  swung.  Two  lamps 
should  be  used,  as  a  more  uniform  illumination  can 
be  obtained  from  two  than  from  one,  and  reflections 
are  avoided.  The  lamps  should  be  wired  to  burn 
independently  of  each  other,  and  the  current  fur- 
nished should  be  uniform,  to  prevent,  as  far  as  pos- 
sible, flickering  and  variation  in  the  intensity  of 
the  light.  Reflectors  are  generally  used  to  concen- 
trate the  light  on  the  copy,  and  are  of  various 
forms.  One  can  be  made  readily  from  an  oblong 
piece  of  tin,  by  bending  it  to  make  its  section  semi- 
circular, the  edges  being  bent  to  fit  around  the 
sides  of  the  lamp.  The  inner  surface  may  be 
painted  white,  or,  better,  etched  off  with  nitric 
3 


26  MANUAL   OF   PHOTO-ENGRAVING. 

acid,  which  will  prevent  reflections  being-  cast  on 
the  copy. 

A  shelf  should  be  built  outside  of  one  of  the 
windows  to  give  facilities  for  sunning  the  silver 
bath.  A  gas  stove  should  be  placed  on  one  of  the 
benches,  for  evaporating  the  bath,  heating  nega- 
tives, etc. 

ETCHING    ROOM. 

C  is  the  etching  room,  which  for  convenience  is 
located  next  to  the  operating  rooms.  7  is  a  sink  of 
ample  capacity  where  the  metal  may  be  polished, 
glass  washed,  and  negatives  turned.  8  is  a  shelf 
for  holding  glass  and  other  articles.  9  and  10  are 
rooms  for  sensitizing  metal,  one  being  designed  for 
line  and  one  for  half-tone  work.  They  should  be 
furnished  with  benches,  shelving,  and  gas  stoves. 
The  illumination  should  be  subdued,  to  prevent  the 
action  of  light  on  the  plates  before  printing,  but 
not  to  such  an  extent  as  is  necessary  for  the  dark- 
rooms for  negative  making. 

The  construction,  arrangement,  and  care  of 
these  rooms  should  be  such  as  to  prevent  the 
accumulation  of  dust,  which  will  cause  spots  in  the 
coating  of  the  plates.  This  remark  will  also  apply 
to  the  darkrooms,  1  and  4. 

In  the  room  used  for  coating  the  line  plates  a 
bench  and  slab  may  be  provided  for  rolling  up  the 
plates.  11  is  a  bench  for  general  purposes,  such  as 
cutting  zinc  upon,  holding  negatives  for  printing, 
etc.  12  is  the  powder  box  to  contain  the  dragon's 
blood    for  the   line   etchings.      In   some   shops   an 


MANUAL   OF    PHOTO-ENGRAVING.  27 

open  box  is  used,  but  it  is  better  to  have  a  closet 
built  around  it  to  prevent  the  powder  from  being- 
carried  about  the  room.  13  is  a  bench  for  a  gas 
stove  for  burning  in  the  plates.  14  and  16  are 
etching  tubs,  placed  near  the  windows,  to  obtain 
ample  light.  15  is  a  sink  or  a  bench  to  hold  a  tray 
of  water  to  rinse  the  plates  after  etching.  17  is 
a  shelf  placed  outside  of  the  window  for  printing 
by  daylight.  An  electric  lamp  should  also  be  pro- 
vided for  the  printing. 

THE    FINISHING    ROOM. 

D  is  the  finishing  room  in  which  numbers  18  to 
23  represent  the  several  machines.  24  and  25  are 
benches  for  mounting  the  plates  upon,  for  holding 
tools,  material,  etc. 

The  machinery  should  be  operated  from  a  line 
of  shafting  which  should  be  provided  with  belt 
shifters,  that  any  machine  may  be  started  or 
stopped  as  desired.  If  the  building  is  equipped 
with  a  power  plant  the  shafting  may  be  operated 
by  a  belt  running  from  some  other  line.  If  the 
place  is  not  thus  equipped  the  power  may  be  ob- 
tained from  a  gas  engine  or  electric  motor. 

E  represents  the  office. 

In  large  establishments  the  half-tone  etching  is 
often  done  in  a  room  separate  from  that  used  for 
line  etching,  but  such  an  arrangement  need  not  be 
considered  as  necessary. 

In  selecting  a  location  for  a  shop  it  is  important 
to  obtain  one  where  there  will  be  an  ample  supply 
of  running-  water  at  all  times  and  where  there  are 


28  MANUAL   OF   PHOTO-ENGRAVING. 

a  number  of  windows,  as  it  is  desirable  to  have 
plenty  of  lig-ht. 

In  fitting-  up  the  shop  economy  should  sometimes 
be  sacrificed  to  completeness  and  convenience,  as 
future  results  ma}'  at  times  justify  an  outlay  which 
mig-ht  at  first  seem  to  be  extravagant. 

The  above  description  is  intended  to  give  only 
general  directions  for  the  shop  arrangement. 
Special  situations  will  require  various  departures 
from  this  plan. 


MANUAL   OF   PHOTO-ENGRAVING.  29 


CHAPTER   IV. 
NEGATIVE   MAKING. 

GENERAL    PRINCIPLES CHEMICALS. 

THE  production  of  a  photographic  negative,  as 
described  hereafter,  depends  upon  the  fact 
that  certain  salts  of  silver  are  so  acted  upon  by  cer- 
tain of  the  component  rays  of  white  light  as  to  be 
changed  in  structure.  The  salts  which  have  been 
found  to  be  thus  sensitive  are  the  iodide,  bromide 
and  chloride  of  silver,  each  producing  results  some- 
what different  from  the  others  and  being  often 
combined  in  certain  proportions  to  obtain  the  qual- 
ities of  all  in  the  resulting  negative.  As  intimated 
above,  not  all  of  the  rays  which  together  form 
white  light  are  effective  in  making  a  change  in 
these  silver  salts,  and  it  is  this  condition  also  which 
renders  photography  possible,  for  the  compounds 
can  be  prepared  for  use  in  a  room  from  which  the 
''actinic"  rays  (as  those  which  affect  the  salts  are 
called),  are  excluded,  the  plate  being  afterwards 
properly  exposed  to  the  action  of  the  "actinic" 
light,  and  the  operation  is  then  completed  by  the 
aid  of  the  "non-actinic"  illumination. 

For  convenience,  it  is  customary  (and,  in  fact, 
essential)  to  use  some  substance  to  hold  the  salts 
and  form  a  film  over  the  surface  upon  which  the 


30  MANUAL   OF    PHOTO-ENGRAVING. 

negative  image  is  to  be  produced.  Collodion  and 
gelatine  are  the  substances  now  universally  em- 
ployed for  this  purpose  in  practical  work.  It  is  not 
customary  in  making  the  sensitive  plate  to  add 
directly  to  the  collodion  or  gelatine  the  required 
salts  of  silver.  It  has  been  found  to  be  more 
advantageous  to  mix  with  these  solutions  the  cor- 
responding salts  of  other  elements,  and  then  sub- 
mit them  to  the  action  of  nitrate  of  silver,  which 
will  cause  the  desired  sensitive  salts  of  silver  to  be 
formed  and  leave  the  nitrates  of  these  elements  as  a 
by-product,  which  in  certain  cases  is  removed  by 
washing  or  precipitation.  For  instance,  if  we  use 
bromide  of  ammonium,  the  action  of  the  nitrate  of 
silver  will  be  to  form  bromide  of  silver  and  nitrate 
of  ammonium,  and  as  stated  above,  the  nitrate  is 
merely  a  by-product,  having  no  value  as  a  sensitive 
agent.  In  the  wet  collodion  process  we  prepare  an 
insensitive  solution,  containing  the  proper  salts, 
and  use  this  solution  to  form  a  film  upon  which  the 
silver  nitrate  is  afterwards  allowed  to  act  to  form 
the  sensitive  salts  of  silver,  the  collodion  acting 
merely  as  a  support  to  hold  the  salts.  In  the  gela- 
tine process  the  silver  nitrate  is  added  to  the  solu- 
tion, thus  directly  forming  the  sensitive  compounds 
within  it,  which,  being  held  suspended  in  a  finely 
divided  condition,  are  said  to  be  in  a  state  of 
emulsion. 

If,  now,  we  have  spread  over  a  plate  of  glass,  or 
other  suitable  substance,  a  coating  in  which  the  sen- 
sitive salts  of  silver  have  been  formed,  we  will  have 
a  film  which,    upon    exposure    to  light  containing 


ZINC     ETCHING  — ORDINARY    OUTLINE     NEWSPAPER    CUT. 
From  drawing  by  A.  B.  Shults. 


MANUAL    OF    PHOTO-ENGRAVING.  31 

actinic  rays,  will  have  certain  changes  produced  in 
its  sensitive  constituents.  If  the  whole  plate  is 
exposed,  it  is  evident  that  the  change  will  be  uni- 
form over  the  whole  surface,  but  if  only  certain 
portions  are  exposed,  the  change  will  take  place  in 
only  those  parts  and  the  intensity  of  the  change 
will  be  proportionate  to  the  intensity  of  the  action 
of  the  light  upon  them.  If,  therefore,  such  a  plate 
is  exposed  in  a  camera  properly  focused  upon  some 
object,  the  rays  of  light  reflected  from  the  object 
will  affect  the  sensitive  salts  in  the  film  and  produce 
an  image  corresponding  in  its  parts  to  the  various 
portions  of  the  object.  If,  however,  the  plate  is 
examined  after  exposure,  there  will  be  no  visible 
image  to  be  detected.  The  appearance  will  be 
exactly  the  same  as  it  was  before  exposure.  To 
bring  out  the  image  it  is  necessary  to  treat  the 
impressed  salts  with  some  substance  which  will  so 
act  as  to  cause  metallic  silver  to  be  deposited  upon 
the  affected  portions.  This  process  is  termed 
"development,"  the  agents  employed  being  called 
"  developers."  Various  compounds  are  used  for 
the  purpose,  such  as  pyrogallol,  eikonogen,  ferrous 
oxalate  and  ferrous  sulphate,  the  latter  being  used 
in  the  development  of  collodion  wet  plates.  When 
a  collodion  wet  plate  is  acted  upon  by  the  developer, 
the  free  silver  nitrate  which  remains  upon  the  sur- 
face of  the  plate  is  decomposed,  the  metallic  silver 
being  deposited  upon  the  impressed  portions  of  the 
film.  While  in  the  emulsion  the  silver  salts  are 
themselves  decomposed. 

The  developers  are  invariably  used  in  the  form 


32  MANUAL   OF   PHOTO-ENGRAVING. 

of  a  solution,  and  when  flowed  over  the  surface  of 
a  plate  those  parts  of  the  image  which  correspond 
to  the  white  parts  of  the  object  appear  first,  then 
the  parts  corresponding-  to  the  half-tones,  and 
finally  the  details  in  the  shadows.  The  light 
reflected  from  the  whites  most  strongly  affect  the 
film,  and  therefore  the  deposit  of  silver  will  be  most 
dense  in  those  parts  of  it  which  correspond  to  the 
white  portions  of  the  object,  the  deposit  in  other 
portions  being  dense  in  proportion  to  the  effect  of 
the  light  reflected  from  the  corresponding  parts  of 
the  object,  while  those  parts  of  the  film  upon  which 
the  blacks  are  produced  will  be  unaffected,  as  the 
black  portions  have  practically  no  actinic  effect 
upon  the  silver  salts. 

The  process  of  development  has  an  important 
place  in  the  production  of  the  negative,  for  any 
carelessness  or  ignorance  in  manipulation  may  ruin 
what  with  proper  treatment  might  result  in  a 
negative  of  excellent  quality.  In  the  wet  collodion 
process  the  developer  is  simply  flowed  over  the 
plate  as  it  is  held  in  the  hand,  the  operation  being 
simpler  and  more  mechanical  than  the  development 
of  the  gelatine  plate.  In  the  development  of  a 
gelatine  negative  the  plate  is  placed  in  a  tray  and 
the  developer  allowed  to  act  until  the  desired  effect 
is  obtained,  it  being  necessary  to  vary  the  propor- 
tions of  the  developer  if  the  plates  have  been  over 
or  under  exposed. 

After  the  negative  has  been  developed,  those 
parts  which  have  not  been  acted  upon  by  the  light 
will   retain   the   same   appearance   that    they   had 


MANUAL   OF   PHOTO-ENGRAVING.  33 

before  development,  and  as  the  unreduced  salts  are 
of  no  value  they  must  be  removed.  To  accomplish 
this  the  plate  is  treated  with  a  solution  which  will 
dissolve  out  these  salts,  and  the  negative  is  then 
said  to  be  "fixed."  The  substances  usually  em- 
ployed to  fix  a  negative  are  cyanide  of  potassium 
or  hyposulphite  of  soda,  in  solution.  The  action  is 
a  chemical  one,  the  corresponding-  salt  of  silver 
being-  formed  and  dissolved  in  the  solution  contain- 
ing an  excess  of  the  fixing  agent.  The  result  is 
that  we  have  an  image  on  the  plate,  dark  in  the 
portions  corresponding  to  the  high  lights  of  the 
object,  with  practically  clear  glass  in  the  parts  cor- 
responding to  the  blacks,  and  if  the  object  is  one 
with  intermediate  tints  or  half-tones,  there  will  be 
gradations  in  the  negative  to  correspond. 

To  be  of  use  in  photo-engraving  the  negative 
must  be  very  intense,  that  is,  the  parts  affected  by 
light  must  be  opaque,  while  the  lines  must  be  as 
clear  glass.  This  result  is  obtained  by  a  further 
treatment  of  the  film  after  fixing,  and  the  method 
will  be  described  in  the  next  chapter. 

Upon  the  time  which  the  plate  is  exposed  in  the 
camera  depends  to  a  great  degree  the  quality  of  the 
resulting  negative.  The  best  results  are  obtained 
only  when  the  exposure  has  been  of  a  duration  of 
time  suited  to  the  conditions.  The  area  of  dia- 
phragm, amount  of  reduction  of  copy,  intensity  of 
illumination,  etc.,  each  has  an  influence  in  deter- 
mining the  necessary  time. 

In  making  negatives  for  photo-engravings  the 
wet  collodion  process  is  at  the  present  time  almost 


34  MANUAL   OF    PHOTO-ENGRAVING. 

universally  employed,  although  some  excellent 
results  may  be  obtained  with  dry  plates  made  for 
the  purpose.  In  the  wet  process  the  plate  is  made 
by  flowing-  over  a  sheet  of  glass  a  collodion  contain- 
ing" in  solution  certain  iodides,  bromides,  or  chlo- 
rides, or  combinations  of  such  salts.  The  plate  is 
then  subjected  to  the  action  of  silver  nitrate  in 
solution,  which  causes  the  sensitive  silver  salts  to 
be  formed  as  explained  above.  The  plate  is 
exposed  and  developed  while  wet,  and  if  the  ma- 
nipulations are  properly  carried  out  the  most 
desirable  results  can  be  obtained. 

THE    COLLODION. 

Various  formula?  for  the  collodion  can  be  em- 
ployed, but  the  following,  which  is  known  to  many 
operators,  is  one  of  the  best,  and  is  an  excellent 
one  for  either  line  or  half-tone  work  : 

Alcohol 8  ounces 

Ether 10 

Iodide  of  ammonium 30  grains 

"        "    cadmium 50       " 

Chloride  of  calcium 10       " 

"  "    strontium 10       " 

Gun  cotton 80       " 

Either  of  the  chlorides  may  be  omitted.  The 
gun  cotton  should  be  easily  soluble.  Anthony's 
Red  Label  is  recommended. 

To  prepare  the  collodion  dissolve  the  gun  cotton 
in  the  ether  and  six  ounces  of  the  alcohol.  Then 
put  the  remaining  two  ounces  of  the  alcohol  in  a 
clean  mortar  and  add  each  salt  separately,  and 
grind  with  the  pestle  until  dissolved.     After  all  of 


HALF-TONE—  150-LINE    SCREEN. 


MANUAL   OF    PHOTO-ENGRAVING.  35 

the  salts  have  been  added  and  dissolved,  pour  the 
solution  into  the  solution  of  gun  cotton  and  shake 
well.  This  collodion  will  usually  be  found  to  work 
well  in  a  few  hours  after  making-,  but  should  it  fail 
to  work  clearly  add  a  few  flakes  of  iodine  to  turn 
toward  a  red  color.  Before  using-,  the  collodion 
should  be  filtered  through  a  tuft  of  absorbent  cot- 
ton placed  in  the  neck  of  a  clean,  dry  funnel  which 
should  be  provided  for  this  purpose  alone.  The 
collodion  bottle  should  also  be  kept  tightly  corked, 
as  the  ether  rapidly  evaporates,  leaving  the  col- 
lodion thick. 

THE     SILVER     BATH. 

To  prepare  the  silver  bath,  dissolve  crystals  of 
silver  nitrate  in  water  until  the  actino-hydrometer 
will,  when  floated  in  it,  register  40.  Distilled  or 
clean  rain  water  should  be  used  if  obtainable,  but 
ordinary  water  as  obtained  from  the  faucets  can 
generally  be  used.  In  any  case  the  bath  after  mix- 
ing should  be  placed  in  the  sun  for  a  day  or  two 
until  it  becomes  perfectly  clear,  as  any  organic 
matter  will  be  acted  upon  by  the  nitrate  and  be 
precipitated.  After  sunning,  the  bath  should  be 
carefully  filtered,  and,  in  order  that  it  may  give 
clear  images,  a  few  drops  of  pure  nitric  acid  added 
until  blue  litmus  paper  will  be  turned  red  if  placed 
in  the  solution. 

The  bath  is  now  placed  in  its  holder,  but  must  be 
"  iodized"  before  good  results  can  be  obtained  with 
it.  If  a  collodionized  plate  is  sensitized  in  it  now, 
the  plate  when  taken  from  the  bath  will  look  thin 
and  be  of  a  light  bluish  color,  and  will  give  a  weak, 


36  MANUAL    OF    PHOTO-ENGRAVING. 

thin  image.  This  is  due  to  the  fact  that  in  a  fresh 
bath  the  silver  salts  when  formed  in  the  film  are 
dissolved  out  by  the  silver  solution.  To  prevent 
this  the  bath  must  be  supplied  with  iodides.  The 
best  method  is  to  place  in  the  bath  a  collodionized 
plate  as  large  as  the  holder  will  take  and  let  it 
remain  several  hours  until  the  salts  are  dissolved 
out  of  its  film  into  the  bath.  If  necessary,  this 
operation  should  be  repeated,  until  the  plates  when 
taken  from  the  bath  will  have  a  rich,  creamy 
appearance,  and  give  images  of  the  desired 
strength.  The  methods  for  caring  for  the  bath 
solution  will  be  given  in  Chapter  VII. 

THE    DEVELOPER. 

The  developer  for  these  plates  is  a  solution  of 
ferrous  sulphate,  which  may  be  dissolved  in  various 
proportions.  The  following  will  be  found  to  give 
good  general   results  : 

Ferrous  sulphate   4l/i     ounces 

Acetic  acid 3  to  2>l/2  "  /  3 

Water 48  "  1^%J^ 

Alcohol 2y2  "  or  q.  s. 

The  crystals  of  iron  should  be  finely  ground  in 
a  mortar  and  then  thoroughly  dissolved.  The  de- 
veloper may  be  made  up  by  measuring  its  strength 
by  the  hydrometer,  in  which  case  it  should  register 
20,  and  to  each  20  ounces  there  may  be  added  \l/> 
ounces  acetic  acid,  and  alcohol  in  sufficient  quantity 
to  make  the  solution  flow  readily.  The  action  of 
the  sulphate  is  to  reduce  the  silver,  as  explained  in 
a  preceding  paragraph,  the  acid  being  used  to 
retard  its  action  and  keep  the  image  clear.     Were 


MANUAL   OF    PHOTO-ENGRAVING.  37 

the  iron  allowed  to  act  alone  it  would  cause  a  rapid 
reduction  over  the  entire  plate  and  veil  the  image. 
The  alcohol  is  used  to  cause  the  developer  to  flow 
readily  over  the  plate,  for  after  the  bath  has  been 
used  for  a  time  it  takes  alcohol  from  the  plates, 
causing-  the  developer  to  flow  in  streaks,  the  addi- 
tion of  alcohol  to  the  developer  aiding-  it  to  flow  in 
an  even  sheet. 

FIXING    SOLUTION. 

Cyanide  of  potassium.     Water. 

Make  in  solution  strong  enough  to  dissolve  the 
unreduced  salts.  Some  operators  use  a  saturated 
solution,  others  prefer  to  use  it  more  dilute.  Hypo- 
sulphite of  soda  may  be  substituted  for  the  cyanide, 
but  the  cyanide  is  recommended. 

INTENSIFYING    SOLUTIONS. 

There  are  several  methods  of  intensifying  nega- 
tives, but  those  most  commonly  used  are  the  cop- 
per and  silver  and  the  mercury  intensifiers.  The 
former  is  generally  favored. 

COPPER    AND    SILVER    METHOD. 

1.  Make  a  saturated  solution  of  copper  sul- 
phate, and  also  one  of  bromide  of  potassium. 

Place  some  of  the  copper  solution  in  a  wide- 
mouthed  bottle,  and  add  to  it  some  of  the  bromide 
solution.  Exact  proportions  are  not  necessary. 
One  part  of  the  bromide  solution  to  six  or  eight 
parts  of  the  copper  will  be  about  right.  In  making 
the  saturated  solutions,  it  is  well  to  use  warm 
water,  as  the  salts  will  more  readily  dissolve. 

2.  Nitrate  of  silver.     Water. 

4 


38  MANUAL   OF    PHOTO-ENGRAVING. 

Make  a  solution  about  25  grains  of  the  silver  to 
the  ounce  of  water.  It  is  not  necessary  in  practice, 
however,  to  measure  the  quantities  exactly.  The 
operator  will  generally  place  a  few  crystals  in  the 
bottle  and  dissolve  in  some  water,  adding-  a  few 
more  crystals  if  the  solution  acts  too  slowly. 

3.  Nitric  acid.     Water. 

Make  weak  solution.  About  one  part  acid  to 
eight  or  nine  parts  water. 

4.  Ammonium  sulphide.     Water. 

One  part  of  the  sulphide  to  about  five  or  six 
parts  of  water,  to  which  a  few  drops  of  ammonia 
may  be  added.     Keep  this  solution  covered. 

MERCURY    METHOD. 

Mercuric  chloride.     Water. 

Make  a  saturated  solution.  Some  ammonium 
chloride  is  usually  added  to  cause  greater  satura- 
tion. 

In  connection  with  this  solution,  solutions  3  and 
4  given  above  are  used. 

CLEARING    SOLUTION. 

1.  Place  some  iodine  crystals  in  a  bottle  with 
some  crystals  of  iodide  of  potassium  and  add  enough 
water  to  make  a  deep  red  solution.  The  quantity 
of  iodide  need  not  be  as  great  as  the  quantity  of 
iodine  used. 

2.  Cyanide  of  potassium.     Water. 
Make  a  very  weak  solution. 

This  solution  is  most  readily  prepared  by  taking 
a  small  quantity  of  the  stronger  fixing  solution, 
and  diluting  it  largely  with  water. 


ZINC    ETCHINGS  — FROM    PEN    DRAWINGS,   GREATLY    REDUCED. 
Drawn  by  A.  Cambersy. 


MANUAL   OF   PHOTOENGRAVING. 


39 


CHAPTER  V. 
NEGATIVE  MAKING  — LINE  NEGATIVES. 

IN  making-  negatives,  the  operator  cannot  exer- 
cise too  much  care  in  every  detail.  The  expe- 
rienced hand  knows  too  well  that  often  carelessness 
in  what  might  seem  to  the  uninitiated  a  trivial 
matter  may  result  in  failure. 

CLEANING    THE    GLASS. 

The  glass  upon  which  the  negative  is  to  be  made 
must  be  scrupulously  clean.  To  provide  for  this 
there  should  be  obtained  two  tubs,  large  trays,  or 
jars,  into  one  of  which  a  strong  solution  of  lye 
should  be  placed,  and  into  the  other  a  quantity  of 
nitric  acid  diluted  with  water.  The  glass  should 
first  be  allowed  to  soak  for  hours  in  the  lye  until 
any  particles  of  matter  adhering  to  it  are  destroyed 
or  loosened.  It  should  then  be  taken  from  it, 
washed  well  to  remove  the  lye  and  any  dirt  from  it, 
and  placed  to  soak  in  the  acid.  When  removed 
from  the  acid  it  should  be  washed  again  and  placed 
in  a  negative  rack  to  drain,  or  if  desired  for  imme- 
diate use  it  may  be  dried  by  rubbing  with  a  clean 
towel,  and  afterward  with  a  piece  of  soft  cotton 
cloth.     Before  collodionizing  it  should  be  carefully 


40  MANUAL    OF    PHOTOENGRAVING. 

dusted  with  a  camel's-hair  brush,  to  remove  any 
specks  which  might  enter  the  bath  or  cause  spots 
in  the  film.  A  number  of  plates  should  be  cleaned 
at  a  time  and  kept  in  a  negative  rack  for  use. 
Some  operators  albumenize  the  glass  by  flowing 
over  it  after  washing  a  solution  of  1  ounce  albu- 
men in  8  or  10  ounces  water,  acidified  with  nitric 
acid.  The  glass,  after  drying  in  a  rack,  is  put 
away  with  the  albumenized  sides  all  one  way. 
Such  glass  does  not  require  an  edging  of  rubber 
before  collodionizing. 

FOCUSING. 

Care  should  be  exercised  in  focusing  to  obtain 
absolute  sharpness  of  the  image  on  the  ground 
glass,  as  any  blurring  of  the  lines  will  render  the 
negative  practically  useless.  Fasten  the  copy  to 
the  board  so  that  the  image  will  occupy  the  center 
of  the  ground  glass,  put  a  large  stop  in  the  lens, 
and  move  the  camera  until  the  image,  when  per- 
fectly sharp  on  the  ground  glass,  is  of  the  size 
desired.  In  general,  the  focusing  should  be  done 
upon  that  part  of  the  copy  about  midway  between 
the  center  and  the  edge,  particularly  if  the  copy  is 
one  of  large  dimensions. 

The  lights  should  be  so  placed  that  the  illumina- 
tion of  the  copy  will  be  as  uniformly  distributed  as 
possible.  In  photographing  large  copies  by  the 
electric  light,  it  is  sometimes  advantageous  to  move 
the  lights  during  exposure,  to  obtain  an  even  illumi- 
nation over  the  whole.  In  photographing  tracings 
or  line  drawings  on  thin  paper,  a  sheet  of  white 


MANUAL   OF   PHOTO-ENGRAVING.  -H 

paper  should  be  placed  back  of  the  copy.  Copy 
which  is  crumpled,  or  which  cannot  be  made  to  lie 
flat  on  the  copy  board,  may  be  placed  in  an  ordinary 
printing-  frame  and  photographed  through  the 
glass.  The  cover  glass  in  such  a  case  should  be 
clear  and  well  cleaned. 

A  small  magnifying  glass  is  often  of  service  in 
focusing  to  examine  the  lines  of  the  image,  espe- 
cially if  the  ground  glass  is  of  coarse  grain,  or  if 
the  reduction  is  great,  or  the  lines  of  the  copy 
indistinct.  With  indistinct  lines  it  often  facilitates 
accurate  focusing  to  place  a  piece  of  newspaper  or 
other  printed  matter  across  the  face  of  the  copy, 
and  focus  on  that,  removing  it  afterwards,  of  course. 
After  the  focus  is  obtained,  fasten  the  camera  in 
position  by  means  of  the  set  screws  at  the  back, 
take  out  the  ground  glass,  remove  the  large  stop 
and  substitute  a  small  one.  In  photographing  line 
work  it  is  necessary  to  use  a  small  stop  to  obtain 
clear  lines,  especially  if  the  lines  on  the  copy  are 
fine,  or  the  reduction  great.  Having  the  copy 
focused,  the  next  operation  is  the 

COLLODIONIZING    AND    SENSITIZING. 

Having  cleaned  and  dusted  the  plate,  dip  a  small 
brush  (or  a  small  stick,  around  one  end  of  which  a 
tuft  of  cotton  has  been  wrapped)  into  a  solution  of 
rubber  in  benzine  (see  Chapter  VIII),  and  run  a 
narrow  strip  of  this  around  the  edge  of  the  plate. 
The  solvent  will  evaporate,  leaving  the  rubber 
around  the  edge,  which  will  prevent  the  film  slip- 
ping from  the  plate.     Now  hold  the  plate  by  one 


42 


MANUAL   OF    PHOTO-ENGRAVING. 


corner  in  the  left  hand  in  a  horizontal  position,  and 
pour  the  collodion  from  the  vial  in  a  pool  near  the 
upper  right-hand  corner  D,  as  shown  in  diagram. 

Use  sufficient  collodion  to 
cover  the  plate  and  move  the 
plate  so  that  it  will  run  first 
up  to  D,  then  to  C,  then  to 
A,  and  finally  to  B,  from 
which  it  is  to  be  drained 
into  the  phial.  While  drain- 
ing, the  plate  must  be  care- 
fully rocked  to  obtain  an 
even  coating.  When  the 
collodion  has  become  set,  in- 
vert the  plate,  place  it  on 
the  dipper  and  lower  steadily  into  the  silver  bath. 
Close  the  cover  to  the  bath  and  let  the  plate  remain 
for  several  minutes,  and  it  will  then  be  ready  for 
exposure. 

EXPOSURE. 

Close  the  darkroom  door  and  have  the  plate- 
holder  resting  on  its  shelf  in  an  upright  position 
and  open  to  receive  the  plate.  Then  draw  the 
dipper  holding  the  plate  from  the  bath.  If  prop- 
erly collodionized  and  sensitized  the  film  should  be 
free  from  any  spots  or  streaks  and  should  have  a 
creamy  appearance,  with  the  silver  solution  on  the 
surface  in  an  even  sheet.  If  the  solution  lies  over 
the  surface  in  greasy  looking  streaks,  return  the 
plate  to  the  bath  at  once,  moving  it  around  for  a 
moment  in  the  solution,  and  let  remain  for  several 
minutes  longer.     When  the  plate  is  found  ready  to 


MANUAL   OF    PHOTO-ENGRAVING.  43 

expose,  let  it  drain  for  a  minute  or  two,  wipe  the 
back  with  a  rag  or  tuft  of  cotton,  then  place  in  the 
holder  so  that  the  film  side  will  be  toward  the  copy 
when  placed  in  the  camera,  close  the  back  of  the 
holder  and  place  it  in  the  position  of  the  ground 
glass  in   the  camera. 

Having  the  cap  on  the  lens  and  the  lights  prop- 
erly placed,  draw  the  slide  from  the  holder,  then 
remove  the  cap  from  the  lens.  The  time  of  expos- 
ure must  be  a  matter  of  experience,  as  it  will  vary 
with  the  character  of  the  lens,  the  intensity  of  illu- 
mination, the  amount  of  reduction  of  the  copy,  etc. 
Short  exposure  gives  broad  lines,  with  lack  of 
intensity  in  the  negative,  and  the  resulting  print 
will  be  lacking  in  detail.  Long  exposure  gives  fine 
lines,  detail  and  density,  but  tends  to  fill  the  fine 
lines.  For  blue  or  weak  lines  give  as  short  an 
exposure  as  practicable,  for  such  lines  tend  to  affect 
the  sensitive  film,  and  if  the  exposure  is  lengthened, 
the  lines  in  the  image  will  fill.  Light  blue  lines 
cannot  be  reproduced  on  the  ordinary  plate.  When 
the  ground  of  the  drawing  is  yellowish,  give  ample 
exposure,  as  such  a  color  does  not  readily  affect 
the  film. 

Shorten  the  exposure  time  in  proportion  as  the 
image  is  reduced  in  size.  If  the  copy  is  brightly 
illuminated  it  will  require  less  time  than  when  the 
light  is  weak.  When  the  exposure  has  been  con- 
sidered sufficient,  replace  the  cap  on  the  lens,  return 
the  slide  to  the  holder,  and  take  the  holder  to  the 
darkroom.    The  plate  is  now  ready  for  development. 


-±4  MANUAL   OF    PHOTO-ENGRAVING. 

DEVELOPMENT. 

This  must  of  course  be  done  by  the  non-actinic 
light  in  the  darkroom.  To  develop  the  image,  hold 
the  plate  horizontally  in  the  left  hand  and  flow  the 
developer  from  a  beaker  or  graduate  over  the  film 
in  one  even  wave  ;  then  holding  the  solution  on  the 
plate,  keep  moving*  the  plate  gently  to  cause  the 
developer  to  flow  from  side  to  side.  The  negative 
image  will  soon  appear,  and  the  time  of  its  appear- 
ance will  indicate  whether  the  exposure  was  prop- 
erly timed.  If  the  proper  exposure  was  given,  the 
image  will  appear  in  a  few  seconds,  the  white 
ground  taking  a  dark  appearance  and  the  lines 
retaining  the  color  of  the  film  before  the  developer 
was  applied.  If,  however,  the  image  flashes  up  at 
once  and  some  or  all  of  the  lines  become  darkened, 
it  indicates  over-exposure  and  the  lines  will  be  filled, 
as  the  whole  surface  has  been  impressed  and  the 
silver  will  be  deposited  to  some  extent  on  those 
parts  which  should  remain  clear. 

If,  on  the  other  hand,  the  image  is  slow  in 
appearing,  and  the  details  are  brought  up  with  dif- 
ficulty, the  plate  has  been  under-exposed.  If  one 
portion  of  the  image  appears  before  another,  it  in- 
dicates uneven  lighting  of  the  copy,  and  when  that 
portion  which  appears  first  is  sufficiently  devel- 
oped, it  should  be  held  to  wash  under  the  tap  while 
the  developer  is  allowed  to  act  upon  the  other  por- 
tions of  the  plate.  Otherwise  the  fine  lines  in  that 
portion  might  fill  by  the  time  the  other  parts 
become   sufficiently   developed.      When    the   whole 


HALF-TONE     FROM     PHOTOGRAPH. 
With  and  without  background. 


MANUAL   OF    PHOTO-ENGRAVING.  45 

image  has  attained  the  proper  intensity,  and  the 
details  are  visible,  the  plate  should  be  immediately 
washed  under  the  tap  to  entirely  remove  the  devel- 
oper and  unreduced  silver  solution.  The  remaining 
operations  can  be  performed  by  daylight. 

FIXING. 

Now  flow  the  fixing  solution  over  the  film  until 
the  unaffected  portions  are  entirely  dissolved,  when 
the  lines  should  appear  as  clear  glass.  Then  wash 
the  plate  well  again,  and  examine  carefully  to  de- 
termine if  the  film  has  proper  density,  if  the  lines 
are  fine  enough,  and  if  all  are  clear.  Some  expe- 
rience will  be  required  to  detect  these  qualities. 
If  any  of  the  lines  are  filled  they  will  have  a  hazy 
appearance,  quite  readily  detected,  but  if  not  too 
badly  filled  they  can  be  cleared  by  a  subsequent 
operation  explained  below.  If  the  plate  is  satisfac- 
tory thus  far,  it  must  be  intensified  to  make  the 
ground  opaque,  for  in  its  present  condition  the 
light  would  pass  through  the  ground  so  readily  as 
to  render  the  negative  useless  for  obtaining  a  print 
upon  the  metal. 

INTENSIFICATION. 

The  intensification  may  be  done  with  either  the 
copper  and  silver  or  the  mercury  intensifiers.  To 
intensify  with  the  former,  flow  over  the  fixed  and 
washed  negative  the  copper  solution,  until  the  film 
becomes  white,  then  wash  well  and  flow  with  the 
silver  solution  until  it  is  blackened  throughout,  then 
wash  well  again.  It  will  usually  be  necessary  to 
repeat  the  process  a  second  time,   and  sometimes 


46  MANUAL   OF    PHOTO-ENGRAVING. 

even  three  or  four  times,  if  the  exposure  has  been 
short,  but  twice  will  as  a  rule  be  sufficient  if  the 
exposure  has  been  rightly  timed.  If  any  portion 
of  the  ground  should  still  appear  thin,  after  the 
other  portions  have  become  sufficiently  dense,  repeat 
the  operation  on  that  part  alone,  to  increase  its 
density. 

If,  after  the  entire  ground  has  acquired  the 
proper  density,  the  lines  all  appear  sharp  and 
clear,  additional  blackness  may  be  given  to  the  film 
by  flowing  with  the  ammonium  sulphide  solution 
No.  4.  Before  using  the  solution  No.  4,  flow  with 
the  dilute  nitric  acid  solution  No.  3,  and  rinse. 
This  will  preserve  clearness.  Wash  thoroughly 
after  blackening  with  the  sulphide  solution.  If  the 
lines  are  at  all  veiled  or  closed,  the  sulphide  is  liable 
to  turn  them  yellow,  and  in  such  a  case  it  should  be 
omitted.  Additional  density  in  the  intensification 
may  at  times  be  obtained  by  treating  the  film  with 
a  dilute  solution  of  iodide  of  potassium,  after  the 
copper  and  before  the  silver  is  used.  This  turns 
the  film  a  lemon-yellow  color.  This  treatment  will, 
however,  sometimes  cause  a  stain  if  the  bath  and 
other  chemicals  are  not  in  a  clean  condition.  The 
solution  is  made  by  dissolving  a  few  crystals  of 
iodide  of  potassium  in  water. 

CLEARING. 

If,  after  intensifying  with  the  copper  and  silver 
solutions,  any  of  the  lines  are  filled,  they  must  be 
cleared.  To  do  this,  flow  over  the  filled  portions  the 
dark  red  solution  of  iodine  and  iodide  of  potassium, 


MANUAL    OF    PHOTOENGRAVING.  47 

and  rinse.  Then  carefully  follow  with  the  very 
dilute  solution  of  cyanide,  applying-  it  until  the 
filled  portions  are  cleared.  If  the  cyanide  solu- 
tion is  any  too  strong-  it  will  dissolve  the  film  also 
and  ruin  the  negative.  During  the  operation  the 
water  should  be  kept  running  from  the  tap  and 
immediately  applied  if  the  action  shows  any  ten- 
dency to  proceed  too  far ;  and  at  times  it  is  to 
advantage  to  let  the  water  run  over  the  plate,  while 
the  cyanide  is  being  applied,  to  cause  the  action  to 
proceed  slowly.  This  treatment  of  the  film  will 
cause  it  to  become  whitened.  To  blacken  it,  the 
ammonium  sulphide  solution  must  be  used  as  di- 
rected above. 

Instead  of  using  the  iodine  solution  strong  and 
the  cyanide  solution  weak,  some  operators  prefer 
to  dilute  the  former  and  use  the  latter  strong, 
intensifying  again  after  the  clearing.  Instead  of 
using  the  solutions  separately,  they  may  be  mixed 
by  adding  cyanide  to  the  iodine  solution  until  the 
color  disappears,  and  diluting  with  water.  The 
solution  is  then  applied  until  the  lines  are  cleared. 
If  the  lines  are  too  badly  filled  it  will  be  impossible 
to  clear  them,  and  the  negative  will  be  worthless. 

THE   MERCURY    METHOD. 

Have  the  mercury  solution  in  a  tray  and  allow 
the  fixed  negative  to  remain  in  it  until  bleached. 
Then  flow  with  the  acid  and  sulphide  solutions  to 
blacken.  For  greater  density,  place  in  the  mer- 
cury again  until  of  a  grayish  color,  and  repeat 
with  the  sulphide  solution,  washing  well  between 


48  MANUAL   OF    PHOTO-ENGRAVING. 

each  operation.  The  sulphide  solution  tends  to 
weaken  the  film,  and  in  washing-  the  negative  after 
its  use  the  water  should  not  be  allowed  to  run  on  it 
with  much  force.  Having  obtained  a  negative  with 
clear  lines  and  opaque  ground,  it  may  be  dried 
spontaneously  or  over  heat  and  is  then  ready  for 
reversing,  the  operations  for  which  will  be  de- 
scribed in  Chapter  VIII. 


MANUAL   OF    PHOTOENGRAVING.  40 


CHAPTER   VI. 

NEGATIVE   MAKING  —  HALF-TONE 
NEGATIVES. 

IN  making-  negatives  from  line  drawing's,  as 
described  in  last  issue,  there  are  no  gradations 
to  be  reproduced,  but  in  obtaining  negatives  from 
photographs  and  wash  drawings  we  have  every 
gradation  from  solid  blacks  to  pure  whites,  which 
must  be  properly  rendered.  In  order  to  obtain  a 
negative  which  will  be  suitable  for  reproducing 
these  gradations  upon  the  metal  plate,  we  break 
up  the  negative  image  in  such  a  manner  that  it  will 
be  formed  of  dots  and  clear  spaces,  the  size  of  the 
dots  varying  to  correspond  with  the  different 
shades  in  the  copy.  This  is  accomplished  by  plac- 
ing in  front  of  the  sensitive  plate  when  in  the  cam- 
era a  glass  plate  so  ruled  as  to  have  alternating 
parallel  opaque  lines  and  clear  spaces.  The  light 
passing  through  the  clear  spaces  produces  the 
desired  effect  upon  the  sensitive  film. 

THE    SCREEN-PLATE. 

The  ruled  plate  which  is  used  for  the  purpose 
described  above  is  commonly  called  the  screen- 
plate.  These  plates  may  have  lines  ruled  in  only 
one  direction,  or  in  several.  The  screen  commonly 
used  has  rulings  in  two  directions,  one  set  of  lines 


50  MANUAL   OF    PHOTO-ENGRAVING. 

crossing-  the  other  at  about  right  angles.  Such 
plates  are  made  by  sealing  together  two  "single 
line "  screens,  ruled  in  opposite  directions,  the 
effect  being  to  produce  a  network  of  the  opaque 
lines.  Having  such  a  cross-line  screen-plate  placed 
in  front  of  the  sensitive  plate  during  exposure,  all 
conditions  being  arranged  to  obtain  the  proper 
results,  the  action  of  the  light  in  passing  through 
the  clear  spaces  is  to  so  act  upon  the  film  that  when 
the  plate  is  developed  the  image  will  be  found  to  be 
made  up  of  opaque  dots  of  varying  size,  those  in 
the  whites  being  largest,  the  size  decreasing  as  the 
tints  in  the  original  grow  darker  until  they  prac- 
tically disappear  in  the  solid  blacks.  A  print  made 
from  such  a  negative  will  have  separate  black  dots 
in  the  high  lights,  which  will  increase  in  size  as 
the  shadows  deepen,  running  into  solid  lines,  the 
details  in  the  shadows  being  formed  of  open  dots, 
which  will  decrease  in  size  as  the  shades  increase 
in  intensity,  until  they  are  absent  in  the  blacks. 
There  is,  therefore,  a  simple  gradation  correspond- 
ing to  the  shades  of  the  original,  each  shade  being 
composed  of  dots  of  a  certain  size. 

A  somewhat  different  effect  than  that  obtained 
with  the  ordinary  single  or  double  line  screen  may 
be  produced  by  using  a  screen  having  the  clear 
spaces  of  different  sizes  arranged  in  groups,  and 
also  having  the  opaque  obstructions  differing  in 
sizes,  and  arranged  in  groups.  The  result  with 
such  a  screen  is  to  obtain  a  printing  surface  made 
up  of  groups  of  dots  and  lines,  in  which  the  indi- 
vidual   members   differ    from   each  other,   but   the 


EFFECT    OF   "FOUR-LINE"    SCREEN. 


MANUAL    OF    PHOTOENGRAVING. 


51 


MR.    LEVY'S    "FOUR-LINE"    SCREEN. 


geometrical  arrangement  being-  similar  throughout 
the  series.  Mr.  Levy  has  produced  such  a  screen 
with  four  sets  of  rulings,  each  set  consisting  of 
parallel  lines.  Two  of  the  sets  are  crossed  at 
right  angles  to  each  other,  and  the  other  two  also 
at  right  angles  to  each 
other,  and  crossing  the 
first  two  at  an  angle 
of  forty-five  degrees. 
The  apertures  are, 
therefore,  in  the  form 
of  right-angled  trian- 
gles, but  the  intersec- 
tions are  so  placed  that 
the  apertures  shall 
vary  in  size,  and  there  are  also  formed  two  dif- 
ferent-sized obstructions  to  the  light,  one  size  by 
the  intersection  of  two  lines,  and  the  other  by  the 
intersection  of  the  four. 

In  the  print  obtained  from  the  resulting  nega- 
tive made  through  such  a  screen,  the  high  lights 
will  be  formed  of  single  dots  corresponding  to  the 
four-line  intersections,  and  in  the  darker  shades 
a  smaller  dot,  corresponding  to  the  two-line  inter- 
section, will  appear,  thus  forming  two  series  of  dots 
which  will  run  through  the  middle  tints,  increasing 
in  size  as  the  shadows  increase  in  intensity,  until 
they  form  continuous  lines.  The  details  in  the 
shadows  will  also  consist  of  a  series  of  open  dots  or 
spaces  corresponding  to  the  clear  apertures  of  the 
screen,  and  as  the  shades  deepen  the  dots  repre- 
senting the  clear  apertures  will  disappear  in  series, 


52  MANUAL   OF    PHOTO-ENGRAVING. 

first  those  corresponding-  to  the  smallest  apertures, 
then  those  corresponding-  to  the  next  size,  and  so  on 
until  there  will  be  but  one  series  of  open  dots  (those 
corresponding  to  the  largest  aperture)  in  the 
shades  next  in  intensity  to  the  solid  blacks.  With 
such  a  screen  the  detail  is  more  truly  rendered,  as 
there  is  obtained  more  than  one  gradation  of  dots 
for  each  shade  in  the  half-tones. 

THE    NEGATIVE. 

A  half-tone  negative  properly  made  from  a  sub- 
ject of  good  quality  should  have  the  dots  so  closed 
in  the  whites  that  the  clear  spaces  between  them 
shall  be  separated  from  each  other,  the  dots  de- 
creasing in  size  as  the  tints  in  the  original  darken, 
until  they  disappear  in  the  solid  blacks.  The  clear 
spaces  in  the  high  lights  should  of  course  be  of 
such  a  size  that  the  dots  in  the  resulting  print  shall 
be  large  enough  to  stand  a  sufficiently  deep  etch. 
There  are  several  factors  which  have  an  influence 
in  determining  the  quality  of  the  negative,  as 
follows  : 

CHARACTER    OF   THE   COPY. 

The  character  of  the  copy  determines  to  a  great 
degree  the  results  obtainable.  Many  photographs 
are  entirely  lacking  in  contrasts,  while  others  are 
as  deficient  in  detail.  The  former  will,  of  course, 
require  a  treatment  to  obtain  brilliancy  in  the  half- 
tone, while  the  latter  will  require  manipulation  to 
obtain  detail  in  the  masses  of  shadow.  The  surface 
upon  which  the  drawing  or  photograph  is  made  will 
also  sometimes  cause  difficulty  in  obtaining  desirable 


MANUAL   OF   PHOTO-ENGRAVING.  53 

effects.  As  a  rule,  smooth  surfaces  are  to  be  pre- 
ferred to  work  from,  as  the  grain  in  rough  surfaces 
will  often  show  to  disadvantage  in  the  reproduction. 
The  color  or  tone  of  the  copy  is  another  element  to 
be  considered.  The  chocolate-brown  tones,  such  as 
were  once  obtained  in  albumen  prints,  give  excel- 
lent effects,  while  lilac  and  bluish  tones  tend  to  give 
flat  results. 

ILLUMINATION    OF   THE    COPY. 

The  illumination  of  the  copy  should  be  uniform, 
and  the  lamps  should  burn  without  flickering  or 
variation  in  intensity.  The  lights  should  be  placed 
so  that  reflections  on  the  copy  will  be  avoided. 
Large  copies  are  more  satisfactorily  lighted  from 
the  skylight  than  with  electric  lamps.  With  a 
bright  illumination  a  shorter  exposure  is  required 
than  with  one  of  less  brilliancy. 

SEPARATION  OF  SCREEN  AND  PLATE. 

If  the  screen-plate  could  be  placed  during  expo- 
sure so  that  the  ruled  lines  would  be  in  contact  with 
the  sensitive  plate,  it  is  plain  that  the  result  would 
be  merely  a  reproduction  of  the  lines  of  the  screen, 
there  being  no  variation  in  the  size  of  the  dots.  In 
order  to  obtain  the  required  variation,  it  is  neces- 
sary to  separate  the  screen  and  plate  that  there 
may  be  a  certain  amount  of  diffraction  of  light 
between  them.  The  effect  of  such  separation  upon 
the  relative  size  of  the  dots  will  vary  with  the  dis- 
tance between  the  plates.  The  nearer  they  are 
together,  the  less  will  be  the  variation,  and  conse- 
quently the  flatter  will  be  the  resulting  negative. 


54  MANUAL   OF    PHOTO-ENGRAVING. 

Therefore,  to  a  certain  extent,  by  varying-  the 
amount  of  separation,  we  may  obtain  detail  or 
contrast  in  the  resulting-  negative.  When  using 
coarse  screens,  it  will  be  found  necessary  to  use 
a  wider  separation  than  with  a  fine  screen,  to 
obtain  similar  results,  all  other  conditions  being 
the  same.  When  the  same  screen  is  used  for  vari- 
ous subjects,  after  a  suitable  separation  has  been 
found  to  give  proper  rendering  of  good  copies,  it 
will  not  usually  be  necessary  to  change  the  dis- 
tance between  screen  and  plate  to  obtain  detail 
or  contrast,  as  these  effects  can  be  secured  by 
altering  the  area  of  the  diaphragm,  as  will  be  ex- 
plained. If  a  certain  screen  and  plate  are  separated 
to  aid  in  obtaining  contrast,  the  exposure  time 
should  be  somewhat  less  than  that  given  when  the 
screen  and  plate  are  nearer  to  each  other.  To 
increase  the  separation  in  the  kit  between  screen 
and  plate,  small  pieces  of  cardboard  are  placed 
between  the  screen  and  the  corner  pieces. 

AREA    OF    DIAPHRAGM    APERTURE. 

Whether  the  half-tone  negative  shall  have  detail 
or  contrast  depends  to  a  great  extent  upon  the 
area  of  the  aperture  in  the  diaphragm  used  during 
exposure.  If  the  exposure  is  made  with  a  small 
aperture  the  resulting  negative  will,  upon  examina- 
tion, be  found  to  have  the  dots  in  the  high  lights 
separated  from  each  other,  and  the  dots  in  the 
shadows  will  be  strong  and  approaching  in  size  to 
those  in  the  high  lights.  The  negative  will  there- 
fore be  made  up  of  a  network  of  clear  lines,  and  a 


HALF-TONE    FROM     PHOTOGRAPH. 
With  ornamented  background. 


MANUAL   OF    PHOTO-ENGRAVING.  55 

print  made  from  it  would  be  formed  of  a  similar 
network  of  solid  lines.  The  resulting-  etching 
would,  therefore,  give  proofs  gray  and  devoid  of 
contrasts.  If,  on  the  contrary,  a  large  aperture  is 
used,  the  high  lig-hts  in  the  negative  will  be  formed 
of  large  dots,  which  will  unite  to  form  a  network 
of  dark  lines  dotted  with  clear  spaces,  separated 
from  each  other,  while  the  dots  will  rapidly  de- 
crease in  size  as  the  depths  in  the  shadows  increase 
in  intensity,  the  blacks  remaining  as  clear  glass. 
A  print  made  from  such  a  negative  would  have  the 
high  lights  made  up  of  separate  dots,  the  middle 
tints  would  be  formed  of  dark  lines  varying  in 
thickness,  and  the  deep  shadows  would  consist  of 
solid  masses.  An  etching  made  from  such  a  print 
would  give  a  "black  and  white"  proof,  and  if  the 
area  of  aperture  has  been  too  large,  detail  will  be 
lost  in  many  places  where  it  should  appear,  the 
gradations  being  buried  in  solid  portions  of  black, 
while  the  whites  will  appear  "chalky,"  and  if  the 
clear  spaces  in  the  negative  have  been  too  small, 
the  resulting  dots  in  the  print  will  not  be  of  suffi- 
cient size  to  stand  a  deep  bite,  rendering  the  plate 
liable  to  smudg-e  in  the  printing. 

There  is  evidently  a  mean  between  the  two 
extremes,  it  being  possible  to  find  a  diaphragm 
having-  an  aperture  with  which  a  negative  can  be 
made  the  print  from  which  will  have  the  dots  in 
the  whites  of  sufficient  size  to  allow  a  sufficiently 
deep  etch,  and  yet  so  separated  that  these  high 
lights  will  appear  of  the  requisite  clearness,  the 
dots  and  lines  in  the  other  portions  being-  of  such 


56  MANUAL   OF    PHOTO-ENGRAVING. 

dimensions  that  in  the  resulting-  print  we  will  have 
a  proper  correspondence  to  the  gradations  in  the 
original.  Not  only  may  a  single  diaphragm  be  used 
to  accomplish  the  desired  result,  but  during  expo- 
sure the  area  of  the  diaphragm  may  be  changed, 
using  a  small  aperture  during  a  part  of  the  expo- 
sure and  a  larger  one  for  the  balance,  the  small  stop 
producing  the  detail  and  the  large  one  the  union  of 
the  dots  in  the  whites. 

It  has  been  assumed  in  the  above  discussion  that 
the  subject  possesses  the  qualities  of  technical  excel- 
lence. If,  however,  a  negative  is  to  be  made  from  a 
copy  which  does  not  fulfill  such  conditions,  the  size 
of  the  diaphragm  aperture  must  be  so  selected  as 
to  produce  either  detail  or  contrasts,  as  the  case 
may  require.  When  the  copy  is  one  which  has 
abnormal  contrast,  a  comparatively  small  stop  will 
cause  dots  to  be  formed  in  the  shadows  of  the  half- 
tone and  thus  give  detail,  which  will  often  be  an 
improvement.  When,  on  the  other  hand,  the  copy 
does  not  have  sufficient  brilliancy,  the  use  of  a 
larger  stop  will  bring  out  the  contrasts.  The 
degree  of  detail  or  contrast  to  be  thus  produced  to 
obtain  the  best  effects  is,  of  course,  a  matter  of 
judgment  on  the  part  of  the  operator.  The  larger 
the  stop  used  the  shorter  should  be  the  time  of 
exposure. 

SHAPE    OF    THE    DIAPHRAGM    APERTURE. 

While  diaphragms  having  round  apertures,  as 
usually  supplied  with  lenses,  have  been  generally 
used  by  operators,  those  having  other  shapes  may 


MANUAL   OF    PHOTO-ENGRAVING. 


57 


be  used,  the  form  of  the  dot  being-  determined  by 
the  form  of  the  aperture.  Mr.  Levy,  of  Philadel- 
phia, has  investigated  the  effect  of  various  forms  of 
the  aperture  upon  the  shape  of  the  dot  in  the  nega- 
tive, and  states  as  a  principle  that  each  transparent 
space  in  the  screen  acts  during  exposure  as  a  pin- 
hole lens,  and  causes  an  image  of  the  shape  of  the 
aperture  to  be  formed  upon  the  sensitive  film. 
From  this  it  appears  that  if  we  use  a  round  aper- 
ture, the  dots  in  the  negative  will  be  round,  a 
square  aperture  will  produce  square  dots,  a  trian- 
gular aperture  triangular  dots,  etc.  It  has  been 
found  that  the  dot  formed  by  the  use  of  a  square 
diaphragm  will  be  stronger  than  the  round  dot, 
and  will  require  a  shorter  exposure  time  to  pro- 
duce, as  it  is  plain  that  square  dots  will  close  up  in 


LEVY    DIAPHRAGMS. 


the  whites  in  less  time  than  round  ones.  Mr.  Levy 
has  invented  several  forms  of  diaphragms,  three  of 
which    are    shown    here,   the  first    form    having   a 


58  MANUAL   OF    PHOTOENGRAVING. 

square  aperture  with  two  corners  extended,  the 
second  having-  the  four  corners  extended,  and  the 
third  having-  a  multiple  aperture  of  four  square 
openings,  the  center  being  closed.  These  dia- 
phragms may  be  made  separate  from  each  other, 
but  by  an  ingenious  mechanical  arrangement  may 
be  combined,  and  the  size  and  form  of  the  opening 
may  be  altered  at  will  to  be  square  or  to  have 
either  of  the  two  forms  illustrated  above,  a  scale 
on  the  lens  tube  indicating  the  size  of  the  aperture 
in  terms  of  the  focal  length  of  the  lens,  and  also 
the  length  of  the  projecting  corners,  or  the  extent 
to  which  the  center  is  inclosed  if  the  second  form  is 
used.  The  diaphragms  having  the  apertures  thus 
formed  are  recommended  for  use  in  making  nega- 
tives from  flat  originals,  as  the  light  in  passing 
through  such  apertures  acts  more  intensely  upon 
the  high  lights  than  upon  the  shadows,  thus  pro- 
ducing more  brilliant  effects  than  can  be  obtained 
with  the  ordinary  forms  of  aperture.  For  subjects 
having  the  proper  contrasts  to  produce  a  brilliant 
negative  the  square  aperture  alone  may  be  used 
during  the  exposure,  but  for  flat  originals  the 
inventor  recommends  the  consecutive  use  of  the 
square  aperture,  then  the  one  with  four  corners 
extended,  and  finally  the  one  with  the  multiple 
apertures. 

EXPOSURE   TIME. 

The  exposure  time  in  making  half-tone  nega- 
tives must  be  determined  by  the  conditions  as  enu- 
merated above.     If  all  the  conditions  are  properly 


MANUAL    OF    PHOTO-ENGRAVING.  59 

adjusted  and  the  exposure  time  is  insufficient  the 
dots  will  not  be  sufficiently  closed,  and  if  the  time 
given  is  too  long-  the  clear  spaces  will  either  be 
filled  or  so  small  that  the  dots  in  the  print  would 
not  be  large  enough  to  stand  a  deep  bite. 

MANIPULATIONS. 

First  see  that  the  screen  is  clean.  A  soft,  clean 
cotton  cloth  will  be  found  useful  in  polishing  it,  and 
any  spots  and  streaks  must  be  removed  from  its 
surface,  or  they  will  be  reproduced  in  the  negative. 
Breathing  upon  the  surface  while  rubbing  will  aid 
in  removing  any  streaks.  When  clean,  place  it  in 
the  kit  and  close  the  springs  upon  it  ;  then  place 
the  kit  in  the  plateholder  so  that  the  screen  will 
be  between  the  lens  and  sensitive  plate  during  ex- 
posure. The  operations  of  developing,  fixing  and 
intensifying  are  similar  to  those  described  for  line 
negatives.  To  expose,  the  plate  after  being  sensi- 
tized is  placed  in  the  kit  behind  the  screen,  the 
plateholder  being  then  placed  in  the  camera.  Dur- 
ing exposure  one  size  of  diaphragm  may  be  used, 
or  the  size  may  be  varied  to  suit  the  conditions. 
Upon  this  point  the  judgment  and  experience  of 
the  operator  must  be  used.  After  exposure  the 
plate  is  developed  until  the  details  appear,  and 
then  fixed.  After  fixing  it  should  be  examined  to 
determine  if  the  proper  qualities  have  been  ob- 
tained. If  the  dots  are  widely  separated  in  the 
high  lights,  and  the  shadows  are  filled  with  strong 
dots,  the  resulting  print  will  be  gray  and  flat.  If 
the  dots  in  the  high  lights  are  closed  up,  and  the 
6 


60  MANUAL   OF    PHOTO-ENGRAVING. 

details  in  the  shadows  are  lacking-,  the  print  would 
be  too  brilliant,  and  would  in  many  cases  have  dots 
too  small  to  allow  the  etching-  to  be  carried  to  a 
sufficient  depth.  In  either  case  the  exposure  should 
be  repeated,  and  the  size  of  aperture  and  exposure 
time  increased  or  diminished  as  required  to  obtain 
the  proper  gradation.  The  beginner  should  use 
but  one  size  of  diaphragm  during  anyone  exposure 
until  he  becomes  familiar  with  the  effects  produced 
by  the  different  sizes  of  the  apertures. 

The  intensification  of  the  negative  increases 
the  size  of  the  dots,  so  that  a  properly  exposed 
negative  need  not  usually  have  the  stipple  in  the 
whites  quite  closed  before  intensifying-,  as  that 
opeiation  will  close  them  up  unless  too  much  sepa- 
rated, and  leave  a  strong-  open  space.  In  some 
cases,  however,  a  slight  union  of  the  dots  will 
not  cause  the  clear  spaces  to  be  too  small  after 
intensifying-.  A  little  experience  will  enable  the 
size  of  the  dots  to  be  properly  judged.  A  small 
magnifying-  glass  is  of  service  in  examining  the 
negative. 

Having  obtained  a  negative  in  which  the  grada- 
tion appears  to  be  correct,  it  must  be  intensified, 
the  process  being  the  same  as  described  for  line 
negatives.  If  the  copper  and  silver  process  is  used 
the  ammonium  sulphide  need  not  be  applied,  as  the 
two  solutions  alone  will  be  sufficient  for  a  properly 
exposed  negative.  One  "dip"  may  close  the  stipple 
sufficiently,  or  it  may  require  two,  and  at  times 
three.  Washing  should,  of  course,  be  thorough 
after  each  operation.     For  properly  made  half-tone 


MANUAL   OF    PHOTO-ENGRAVING.  61 

negatives  no  such  clearing-  process  as  described  for 
line  negatives  is  necessary.  After  intensification, 
the  negative  is  dried  and  prepared  for  printing 
from.  An  intelligent  application  of  the  principles 
stated  in  the  preceding  paragraphs  will  enable  the 
operator  to  produce  negatives  of  good  quality. 


62  MANUAL   OF   PHOTO-ENGRAVING. 


CHAPTER   VII. 

NEGATIVE    MAKING  — CAUSES    OF    DE- 
FECTS IN   COLLODION  NEGATIVES  — 
CARE   OF   SILVER   BATH. 

THERE  are  various  defects  which  are  liable  to 
occur  in  the  making-  of  collodion  negatives, 
which  may  be  due  to  faults  in  the  chemicals,  or  lack 
of  care  in  manipulation.  The  following"  are  the 
most  common : 

Fog-,  by  which  is  meant  a  filling  up,  or  deposit, 
in  those  portions  of  the  image  which  should  remain 
clear.     It  may  be  caused  by  : 

Actinic  light  entering  camera,  plateholder  or 
darkroom,  and  striking  the  sensitive  plate. 

Insufficient  acid  in  developer  or  in  bath. 

An  unripened  collodion. 

Over-exposure. 

Over-development. 

Developer  too  strong  or  too  warm. 

Fumes  of  chemicals. 

Transparent  spots  in  the  film  may  be  caused 
by: 

Dust  in  the  collodion,  in  the  bath,  or  on  the 
plate. 

Excess  of  iodides  in  the  bath. 


MANUAL   OF    PHOTO-ENGRAVING.  63 

Undissolved  salts  in  the  collodion. 

Streaks  in  the  film  may  be  due  to  : 

Improper  flowing  of  the  collodion. 

Scum  on  surface  of  bath. 

Bubbles  or  specks  of  dust  floating-  in  collodion. 

Removing  plate  from  bath  too  soon. 

Alcohol  in  the  bath,  in  which  case  the  streaks 
will  be  rather  broad  and  wavy,  and  run  in  the  direc- 
tion of  the  dip. 

Developer  containing  insufficient  alcohol. 

Developer  striking  film  with  too  much  force. 

Developer  too  strong. 

Collodion  too  thick,  or  over-iodized. 

Dirty  plates. 

Dirty   plateholder,  which  will  sometimes  cause 
blotches  like  "oyster  shells." 
=—    Thin  images  may  be  caused  by  : 

A  weak  or  insufficiently  iodized  bath. 

Under-exposure. 

Poor  lighting  of  copy. 

Blurred  images  may  be  caused  by  : 

Improper  focusing. 

Camera  being  jarred  during  exposure. 

Uneven  density  of  film  may  be  caused  by  : 

Uneven  lighting  of  copy. 

Uneven  coating  of  collodion. 

CARE   OF   THE   SILVER    BATH. 

To  obtain  uniformly  good  negatives  requires 
that  the  silver  bath  be  kept  in  proper  condition. 
Every   well-regulated    establishment     has    several 


•34  MANUAL   OF    PHOTO-ENGRAVING. 

baths,  so  that  when  one  needs  rectifying-  another 
can  be  used  without  causing-  delay.  The  following 
rules  will,  if  followed,  keep  the  bath  in  proper 
order  : 

1.  Keep  it  covered. 

2.  Isolate  it  from  other  chemicals. 

3.  Keep  the  hands  clean  while  dipping  plates  or 
handling  the  bath. 

4.  Skim  the  top  every  morning  with  a  strip  of 
clean  paper. 

5.  Filter  often  through  absorbent  cotton. 

6.  Keep  the  strength  up.  It  does  not  waste 
silver  to  do  so.  Some  clean  saturated  solution 
can  be  added  to  the  bath  occasionally  when  it  is 
in  use. 

7.  When  the  bath  becomes  charged  with  alcohol 
boil  it  down.  By  putting  some  water  in  the  vessel 
in  which  it  is  boiled,  and  pouring  the  bath  into  it, 
some  of  the  iodide  will  be  precipitated,  and  aid  in 
keeping  the  bath  from  becoming  over-iodized.  Then 
place  over  heat  and  let  it  steam  until  the  odor  of 
alcohol  is  entirely  gone.  It  is  generally  best  to  let 
it  boil  down  to  a  small  volume.  Then  test  with  the 
hydrometer,  and  if  necessary  add  clean  water  to 
make  it  register  50.  Then  filter  well,  and  it  is 
ready  for  use  again.  If  it  fails  to  work  clear,  add 
a  few  drops  of  nitric  acid  C.  P. 

8.  To  remove  organic  impurities  add  to  the  bath 
enough  permanganate  of  potassium  solution  to  turn 
pink,  and  place  in  a  clean  bottle  in  the  sun  for  sev- 
eral hours,  and  filter. 

9.  Matter  in  suspension  can  usually  be  removed 


HALF-TONE  — 35-LINE    SCREEN. 


MANUAL   OF   PHOTO-ENGRAVING.  65 

by  neutralizing-  the  bath  with  bicarbonate  of  soda, 
and  sunning-.     Filter  and  acidify  ag-ain.' 

10.  If  the  bath  becomes  over-iodized,  pour  it 
into  some  clean  water  to  precipitate  the  iodide, 
filter,  and  boil  down  to  required  streng-th.  If  the 
bath  is  evaporated  at  proper  intervals,  and  the 
iodide  removed  as  directed  in  paragraph  7,  it  will 
not  become  over-iodized. 


6Q  MANUAL   OF    PHOTOENGRAVING. 


CHAPTER   VIII. 

REVERSING   NEGATIVES. 

In  order  that  the  proof  from  the  etching-  may 
appear  unreversed  as  regards  right  and  left,  it  is 
necessary  to  reverse  the  negative  before  obtaining 
the  print  from  it.  There  are  four  methods  by 
which  this  may  be  done,  as  follows  : 

1.  The  sensitive  plate  may  be  so  placed  in  the 
holder  that  the  glass  side  will  be  turned  toward  the 
copy,  allowance  being  made  in  focusing-  for  the 
thickness  of  the  glass.  The  springs  of  the  plate- 
holder  must  be  specially  arranged  to  hold  the  plate 
when  this  method  is  used. 

2.  The  image  may  be  taken  from  the  reflection 
of  the  copy  in  a  mirror,  or  what  amounts  to  the 
same  thing. 

3.  By  having-  a  glass  prism  with  silvered  hy- 
pothenuse  arrang-ed  to  fasten  to  the  front  of  the 
lens,  the  rays  of  light  being-  reflected  from  it 
through  the  lens  and  onto  the  sensitive  plate.  A 
modification  of  this  arrangement  has  the  prism  as 
a  fixed  part  of  the  lens. 

4.  By  stripping  the  film  from  the  glass  support 
and  placing  in  a  reversed  position.  The  two 
methods  last  mentioned  are  those  usually  employed. 


MANUAL  OF   PHOTO-ENGRAVING.  67 

The  construction  of  the  prism  suggests  its  method 
of  use. 

For  turning-  the  collodion  film  it  must  be  coated 
with  the  following-  solutions  : 

RUBBER    SOLUTION. 
Rubber  cement. 
Benzine,  naphtha,  or  benzole. 

Add  sufficient  of  the  solvent  to  the  cement  to 
make  a  thin  solution. 

PLAIN    COLLODION. 

Alcohol .    6  ounces 

Ether 6  ounces 

Gun  cotton 120  grains 

Castor  oil 1%  to  2  drams 

When  the  film  of  the  negative  is  dry  and  cold, 
flow  over  it  the  rubber  solution,  and  place  in  the 
negative  rack  until  dry.  AVhen  the  rubber  is  dry, 
flow  the  collodion  over  the  film,  and  also  let  dry. 
The  collodion  may  be  set  fire  to  while  it  is  wet 
and  burned  off,  if  desired,  but  this  sometimes 
causes  a  blistering  of  the  film.  After  the  collo- 
dion is  dry,  cut  the  film  to  the  desired  size  around 
the  image.  If  the  cut  is  to  be  rectangular,  the 
negative  should  be  placed  on  a  board  or  table  with 
a  straight  edge,  and  a  T-square  and  triangle  be 
used  in  cutting  the  lines.  If  the  board  has  two 
edges  at  right  angles  to  each  other,  the  T-square 
alone  will  answer  the  purpose.  After  the  film  is 
cut  let  the  negative  rest  in  a  tray  of  water  until  the 
film  is  loosened,  then  lift  one  corner  with  a  knife 
until  it  mav  be  taken  between  the  thumb  and  finger 


68  MANUAL    OF    PHOTO-ENGRAVING. 

of  one  hand,  raise  from  the  glass,  take  hold  of  the 
adjacent  corner  also,  and  strip  from  glass  and  lay 
the  film  in  reverse  upon  a  second  sheet  of  clean 
glass  wet  with  water.  Then  lay  upon  the  film  a 
sheet  of  wet  paper,  and  rub  the  squeegee  over  it 
in  various  directions  to  remove  all  of  the  water. 
After  this  is  done,  hold  face  down  over  the  gas 
stove  until  the  paper  begins  to  dry,  then  remove  it 
and  heat  the  film,  to  thoroughly  dry  it,  and  place  in 
rack  to  cool. 

If  the  film  refuses  to  strip  from  the  glass  after 
soaking  in  the  water,  or  if  an  albumen  substratum 
has  been  used  under  the  original  collodion  film, 
place  the  plate  to  soak  in  a  solution  of  acetic  acid. 
Curling  of  the  film  after  transfer  is  sometimes 
caused  by  insufficient  oil  in  the  collodion.  Should 
the  film  fail  to  adhere  to  the  glass  after  stripping, 
flow  under  it  a  thin  gum-arabic  solution,  squeegee 
and  dry  as  usual.  Flowing  the  collodion  or  rubber 
over  the  plate  while  warm  will  cause  bubbling. 
The  collodion  will  at  times  bubble  also  on  a  cold 
plate.  This  may  be  remedied  usually  by  flowing 
some  ether  over  it  when  it  has  just  set.  It  is  cus- 
tomary in  engraving  establishments  to  turn  several 
negatives  upon  one  sheet  of  glass  and  print  all 
together  on  the  same  sheet  of  metal.  Negatives 
made  with  the  prism  will  require  varnishing  before 
being  used  to  print  from. 


MANUAL   OF   PHOTO-ENGRAVING.  69 


CHAPTER   IX. 

ETCHING  — LINE   WORK. 

CERTAIN  organic  solutions  or  mixtures  con- 
taining- a  bichromate  will,  when  reduced  to  a 
dry  state,  be  so  affected  by  actinic  light  as  to  become 
insoluble.  Upon  this  principle  depends  the  opera- 
tions for  making  etched  plates  as  described  here- 
after. If  a  metal  plate  is  coated  with  such  a 
solution,  the  solution  being  allowed  to  dry  in  a  film 
upon  the  plate,  and  then  exposed  to  light  under  a 
negative,  the  light  will  pass  through  the  clear  por- 
tions of  the  negative  and  render  the  coating  under 
those  portions  insoluble,  the  other  portions  of  the 
coating  remaining  soluble,  as  they  are  protected 
by  the  opaque  parts  of  the  negative.  These  solu- 
ble parts  can  then  be  removed,  leaving  the  metal 
bare  between  the  lines  of  the  image  formed  by  the 
parts  of  the  coating  affected  by  light.  The  image 
being,  by  certain  operations,  rendered  impermeable, 
a  solution  can  be  applied  to  the  plate  which  will 
etch  the  metal  away  around  these  lines,  and  thus 
leave  the  image  in  relief. 

PREPARATION    OF    THE    METAL. 

The  metals  commonly  used  for  the  purpose  of 
making  these  plates  are  copper  and  zinc,  the  latter 


70  MANUAL    OF    PHOTO-ENGRAVING. 

being-  used  universally  for  commercial  work  in  line 
etching-,  while  the  former  is  used  principally  in 
making  half-tone  plates.  The  metal  may  be  pol- 
ished by  machine  or  by  hand,  the  latter  method 
being  used  in  most  establishments  of  moderate  size. 
To  polish  the  metal  by  hand  a  board  should  be  fitted 
in  an  inclined  position  in  the  sink  so  that  water 
from  the  tap  can  run  upon  it  when  desired,  a  couple 
of  nails  being  driven  at  the  lower  portion  to  hold 
the  metal  in  position  when  lying  upon  the  board. 

If  the  metal  is  obtained  polished  from  the  deal- 
ers, it  will  be  necessary  to  use  the  charcoal  only  to 
prepare  the  surface  for  coating.  If  it  is  unpolished 
it  should  first  be  rubbed  with  pumice  stone  or 
Scotch  hone  until  the  roughness  is  removed,  and 
then  finished  with  the  charcoal.  If  the  pumice 
stone  is  used,  its  polishing  surface  should  first  be 
ground  flat  and  smooth,  otherwise  it  will  scratch 
the  metal.  While  being  polished  the  metal  should 
be  kept  wet  from  the  tap,  being  rubbed  in  one 
direction  only  with  the  pumice  stone  or  hone  and 
in  the  transverse  direction  with  the  charcoal, 
the  end  of  the  charcoal  being  used.  If  any  flaws 
are  detected  in  the  surface  of  the  metal  they  must 
be  removed  by  punching  from  the  back  as  described 
below.  Place  a  pair  of  calipers  so  that  one  point 
shall  be  directly  over  the  flaw,  the  other  being 
directly  under  it.  Press  the  latter  against  the  back 
of  the  plate  so  as  to  leave  a  scratch,  the  end  of 
which  will  indicate  the  location  of  the  flaw.  Then 
turn  the  plate  face  down  upon  a  polished  iron  slab, 
place  the  end  of  a  punch  over  the  flaw  as  indicated 


VIGNETTED     HALF-TONE     FROM     WASH     DRAWING. 
Drawn  by  J.  C.  Leyendecker. 


By  courtesy  E.  A.  Weeks  &  Co.,  Chicago. 


MANUAL  OF  PHOTO-ENGRAVING.  71 

and  strike  the  other  end  of  the  punch  with  the 
hammer,  which  will  bring-  the  flaw  up  to  the  sur- 
face. Then  polish  again  until  the  surface  of  the 
plate  is  free  from  scratches  and  pits.  The  condi- 
tion of  the  finished  surface  will  depend  largely  upon 
the  charcoal.  Some  charcoal  is  gritty  and  leaves 
scratches  which,  if  deep  enough,  would  show  in  the 
etching.  Such  grittiness  can  often  be  removed  by 
soaking  the  charcoal  in  water  or  the  jar  of  dilute 
acid. 

LINE   ETCHING. 

SENSITIZING    SOLUTION. 

Albumen  from  fresh  egg 1  ounce 

Water 8  ounces 

Bichromate  of  ammonium 15  to  20  grains. 

Dissolve  the  bichromate  in  the  water,  add  to  the 
albumen  and  beat  up  well  with  the  egg-beater  in  a 
bowl  or  mortar.  Filter  until  clean.  Some  etchers 
add  a  few  drops  of  ammonia  to  the  solution. 

COATING    THE    PLATE. 

Having  polished  the  plate,  file  the  roughness 
from  the  edges,  wash  it,  let  some  water  remain  on 
the  surface,  and  carry  it  to  the  room  used  for  coat- 
ing and  drain  the  water  off.  Then  pour  some  of 
the  sensitizing  solution  to  cover  the  plate  and  drain 
it  off  at  one  corner,  repeating  two  or  three  times, 
draining  at  different  corners  to  equalize  the  coat- 
ing.    Specks  of  dirt  or  bubbles  should  be  removed. 

Then  hold  the  plate  over  the  gas  stove  and 
warm  until  dry,  keeping  it  slightly  inclined  to  allow 
7 


72  MANUAL    OF    PHOTO-ENGRAVING. 

any  surplus  fluid  to  drain.  A  little  practice  will 
enable  an  even  coating-  to  be  obtained.  When  the 
plate  is  dry,  allow  it  to  cool  in  the  dark  and  it  is 
then  ready  for  printing-. 

PRINTING. 

See  that  the  heavy  glass  which  is  used  for  the 
bed  plate  in  the  printing  frame  is  clean,  and  also 
the  back  of  the  negative.  Any  grit  between  the 
two  will  sometimes  cause  them  to  crack  when  the 
pressure  is  brought  to  bear.  Also  see  that  there 
is  no  grit  in  the  rabbet  of  the  frame.  Then  place 
the  negative,  film  side  up,  upon  the  bed  plate,  and 
carefully  place  the  coated  plate  face  down  upon  it. 
Place  the  back  of  the  frame  upon  the  metal  (usually 
with  a  pad  of  felt  or  some  folded  papers  between), 
lay  the  bars  across  and  fasten  at  the  ends,  and 
turn  the  screws  until  sufficient  pressure  is  obtained 
to  make  contact  between  the  plate  and  negative. 
Then  place  the  plate  in  the  light  to  print.  If  in 
sunlight,  support  the  frame  so  that  the  rays  will 
strike  directly  upon  the  face.  If  the  electric  light 
is  used,  give  half  of  the  exposure  while  the  frame 
rests  upon  its  side,  then  turn  it  to  rest  upon  the 
opposite  side,  and  give  the  balance  of  the  exposure. 
If  the  negative  is  a  large  one,  keep  the  light  swing- 
ing, to  equally  illuminate  the  whole  surface.  Do 
not  allow  the  printing  frame  glass  to  become  too 
hot,  or  it  will  crack.  The  exposure  time  will  ,Tary 
from  one  to  three  minutes  in  the  sunlight  and  from 
three  to  ten  minutes  in  the  electric  light.  It  will 
require  but  little  experience  to  judge  of  it  properly. 


MANUAL    OF    PHOTO-ENGRAVING.  <•> 

ROLLING    UP    AND    DEVELOPING. 

After  the  plate  has  been  sufficiently  printed  it 
must  be  rolled  up  with  transfer  ink  to  obtain  the 
image.  Upon  the  slab  provided  for  the  purpose, 
place  a  little  of  the  ink,  and  with  a  knife  spread  it 
in  a  line  across  one  end  ;  then  with  the  composition 
roller  distribute  it  in  an  even  coating-  over  the  slab. 
(Lifting-  the  roller  from  the  slab  while  rolling  will 
aid  in  obtaining  an  even  coating.)  If  any  particles 
of  hardened  ink  or  other  matter  cling  to  the  roller, 
remove  them  with  turpentine  and  a  rag.  When  the 
roller  has  an  even  coating  of  the  ink  on  it,  roll  it 
over  the  face  of  the  zinc  until  it  also  is  evenly 
coated.  The  ink  on  the  zinc  should  not  be  too 
thick  ;  the  metal  should  appear  faintly  through  it. 
If  the  ink  should  be  too  thick  on  the  metal,  clean 
the  roller  with  turpentine,  and  when  dry  roll  it 
over  the  zinc  and  it  will  remove  a  good  deal  of  the 
ink.  The  ink  coating  should  be  heavy  enough,  of 
course,  to  absorb  enough  dragon's  blood  and  form 
sufficient  resist  to  the  acid  when  burned  in. 

In  cold  weather  the  ink  will  sometimes  refuse  to 
distribute  properly  under  the  roller.  In  such  a 
case  wet  it  with  a  few  drops  of  turpentine,  or  warm 
the  slab,  and  this  difficulty  will  be  removed.  The 
roller  should  be  kept  free  from  dirt,  and  in  starting 
work  for  the  day  the  slab  and  roller  should  be 
cleaned  with  turpentine  and  fresh  ink  used.  A 
little  experience  will  enable  the  worker  to  judge 
when  the  plate  is  properly  rolled  up.  When  the 
proper  coating  of  ink  is  obtained  upon  the  metal, 


<4  MANUAL    OF    PHOTO-ENGRAVING. 

place  the  plate  in  a  tray  of  clean  water  (or  hold  it 
under  the  tap)  and  rub  the  surface  carefully  with  a 
tuft  of  wet  absorbent  cotton.  The  parts  of  the 
coating-  which  were  not  affected  by  the  light  will 
rub  away,  leaving-  the  image  in  black  lines.  If  the 
exposure  has  been  properly  timed,  the  lines  will  all 
remain  unbroken  upon  a  clean  ground  of  metal.  If 
the  plate  was  under-exposed,  many  of  the  lines  will 
rub  away,  and  if  over-exposed  the  ink  will  cling  to 
parts  from  which  it  should  separate.  In  such  a 
case  a  few  drops  of  ammonia  added  to  the  water  in 
the  tray  will  often  enable  it  to  be  removed.  Rub 
the  image  with  the  cotton  until  all  of  the  lines  are 
clean  and  sharp,  being  careful  to  see  that  the  spaces 
are  free  from  any  adhering  ink.  Then  dry  the 
plate  by  draining  and  warming  over  the  gas  stove. 
By  patting  it  before  warming  with  a  piece  of  damp 
chamois  skin,  rolled  into  a  pad,  the  surplus  water  is 
readily  removed. 


READY  FOR  ETCHING. 


AFTER  ROUTING. 


With    a   camel's -hair  brush  paint   in  with   the 
transfer  ink,  wet  with  turpentine,  any  parts  of  the 


MANUAL   OF    PHOTO-ENGRAVING.  75 

lines  which  may  be  broken,  and  also  the  largest 
open  spaces  as  shown  in  the  cut,  one  being-  the 
appearance  of  the  plate  when  thus  painted  in,  and 
the  other  the  appearance  after  routing-  and  finish- 
ing. 

The  painting  in  of  these  spaces  supports  the 
roller  and  prevents  smudging  in  the  subsequent 
rolling. 

POWDERING    AND    ETCHING. 

After  the  plate  has  been  thus  painted,  it  is  ready 
for  powdering.  Have  some  dragon's  blood  in  the 
powder  box,  and  dump  it  upon  the  surface  of  the 
plate,  and  then  brush  off  the  surplus  with  a  broad 
soft  brush,  finishing  with  a  tuft  of  dry  cotton  until 
the  metal  spaces  are  clean.  The  dragon's  blood 
will  adhere  to  the  ink.  The  plate  is  now  held  over 
the  gas  stove  and  heated  until  the  powder  incorpo- 
rates with  the  ink,  as  shown  by  its  turning  a  rather 
glossy  black.  There  are  two  grades  of  dragon's 
blood,  one  a  dark  red  color,  the  other  lighter  in 
color.  The  latter  will  burn  in  more  readily  than 
the  other,  and  form  a  strong  resist.  After  the 
plate  is  thus  heated  paint  the  back  with  asphalt 
varnish,  cool,  and  the  image  being  now  able  to 
resist  the  acid,  the  plate  is  ready  for  the  first  bite. 

The  acid  used  for  this  bite  should  not  be  very 
strong.  The  proportions  are  not  arbitrary.  The 
beginner,  however,  may  take  about  two  and  one- 
half  parts  of  the  commercial  nitric  acid  to  thirtv- 
two  parts  of  water,  for  the  first  etch.  Place  this 
in  the  etching  tub  and  immerse  the  plate    in   it. 


7G 


MANUAL    OF    PHOTO-ENGRAVING. 


Then  rock  the  tub,  and  as  the  action  of  the  acid 
proceeds,  keep  the  plate  clean  by  brushing-  with  the 
bristle  brush  used  for  the  purpose.  This  bite  need 
not  be  deep.  Three  to  five  minutes  will  be  suffi- 
cient, when  the  metal  will  be  found  so  etched  away 
as  to  leave  a  line  in  slight  relief.  Then  remove  the 
plate  from  the  acid,  rinse,  dry  off  the  surplus 
water  with  a  towel  or  the  damp  chamois,  and  warm 
over  the  stove.  Before  continuing  the  etching-  the 
sides  of  the  lines  must  be  protected  to  prevent  the 
acid  attacking  them  and  causing  breaks.  This  is 
usually  done  by  "powdering  four  ways,"  as  fol- 
lows :  Take  the  plate  to  the  powder  box,  and  dump 
some  of  the  dragon's  blood  on  it,  then  beginning  at 
one  edg*e  of  the  plate  pass  the  brush  over  it  from 
that  side  to  the  side  opposite,  so  that  the  powder 
will  be  brushed  against  the  sides  of  the  lines. 


<r 


v 


A 


For  instance,  in  above  diagram,  if  the  brush  is 
started  at  the  side  D,  brush  in  direction  indicated 
by  the  arrow  A  toward  side  B.     Hold  the  brush 


ZINC     ETCHING  — CRAYON     EFFECT. 
From  sketch  by  Frank  Holme. 


MANUAL    OF    PHOTO-ENGRAVING.  '»  < 

upright,  and  brush  in  even  sweeps  without  lifting- 
from  one  extreme  edge  to  the  other.  When  the 
spaces  between  the  lines  are  clean,  and  the  lines  all 
"covered,"  heat  the  plate  again  to  cause  the  pow- 
der to  adhere  to  the  lines,  and,  when  cool,  powder 
in  a  similar  manner  in  the  direction  of  arrow  B, 
moving  the  brush  from  A  to  C,  and  heat  again. 
Repeat  the  powdering  in  the  remaining  two  direc- 
tions, heating  after  each,  and  if  properly  done  the 
powder  will  adhere  so  as  to  protect  the  lines  on  all 
sides. 

When  cool,  the  plate  is  ready  for  the  second 
bite.  The  etching  is  proceeded  with  the  same  as  at 
first,  the  time  being  increased  somewhat,  and  when 
it  has  been  carried  far  enough  the  plate  is  again 
rinsed,  dried  and  powdered  as  before,  and  placed  in 
the  bath  to  etch  again,  the  strength  of  bath  and 
time  being  increased.  When  the  action  has  again 
proceeded  sufficiently,  it  is  removed  from  the  acid 
and  prepared  for  the  fourth  bite.  This  may  be 
done  by  simply  powdering  again  as  for  the  other 
bites,  but  it  is  customary  with  many  etchers  to  roll 
the  plate  up  again  to  form  a  thick  coating  of  ink 
over  the  tops  of  the  lines  before  powdering  for  the 
fourth  bite,  so  that  the  ink  will  run  down  the  sides 
of  the  lines  during  the  heating  and  form  a  more 
impermeable  coating.  This  rolling  up  is  best  done 
with  the  leather-covered  roller.  After  this  rolling 
up  the  plate  is  powdered  again  and  given  the  fourth 
bite.  The  four  bites  will,  as  a  rule,  be  all  that  are 
necessary  for  the  ordinary  work,  and  the  plate  can 
be  cleaned,  routed  and  mounted. 


78  MANUAL   OF    PHOTO-ENGRAVING. 

A  "clean  bite"  may,  however,  be  given  to 
remove  the  "shoulder"  from  the  lines.  During 
the  operation  of  powdering-  and  etching,  the  lines 
are  not  always  etched  straight  down,  but  are 
formed  in  steps  which,  if  prominent,  will  print  up 
and  make  a  broad  line  in  the  resulting  proof.  To 
remove  this  "shoulder  "  to  a  certain  extent  the  ink 
and  powder  are  first  removed  from  the  plate  after 
heating  and  flowing  with  lye  or  alcohol,  using  a  stiff 
scrubbing  brush.  A  coating  of  ink  is  then  rolled 
over  the  top  of  the  lines  and  powdered  and  heated 
so  that  while  the  top  will  be  protected  the  sides 
will  remain  bare.  The  plate  is  then  placed  in  a 
weak  solution  of  acid  and  etched  for  a  few  moments, 
the  effect  being  to  etch  away  some  of  the  shoulder 
and  give  a  sharper  line.  This  must  be  done  with 
great  care.  After  cleaning,  the  plate  is  ready  for 
the  finisher. 

The  strength  of  acid  and  time  of  etching  for 
each  bite  cannot  be  stated  arbitrarily.  They 
depend  largely  upon  the  character  of  the  etching, 
some  lines  not  being  able  to  stand  the  action  as 
long  as  others,  and  it  requires  some  experience  to 
judge  when  the  biting  has  proceeded  far  enough, 
the  object  being  to  allow  the  acid  to  act  as  far  as 
possible  without  undercutting  or  breaking  the  lines. 
The  experienced  etcher  does  not,  as  a  rule,  measure 
his  acid,  and  judges  by  appearance  of  the  lines 
when  the  operation  must  cease.  The  beginner, 
however,  may  commence  by  using  the  following 
proportions  for  the  solution  and  times  for  biting  : 


MANUAL    OF    PHOTO-ENGRAVING.  79 

First  bite  —  2)4   parts  acid  to  32  parts  water. 

Etch  two  to  three  minutes. 
Second  bite  • — 2**2  parts  acid  to  32  parts  water. 

Etch  five  to  six  minutes. 
Third  bite  —  3^2  parts  acid  to  32  parts  water. 

Etch  eight  to  ten  minutes. 
Fourth  bite  — •  5  to  8  parts  acid  to  32  parts  water. 

Etch  ten  to  twelve  minutes. 

The  beginner  should  start  with  subjects  having 
strong  lines,  and  should  carefully  watch  the  action 
until  he  has  acquired  such  experience  that  he  can 
etch  without  timing  the  bites.  For  regular  work 
four  bites  is  usually  sufficient,  but  some  plates  may 
be  given  five  and  others  will  require  only  three, 
the  latter  being  the  case  when  the  lines  are  close 
together.  In  many  establishments  the  clean  bite  is 
omitted,  care  being  taken  to  powder  the  plate  clean 
so  that  no  excess  of  powder  will  cling  to  the  lines 
and  form  a  large  shoulder.  For  a  clean,  deep  job 
the  plate  may  have  the  spaces  routed  before  the 
last  bite. 

In  powdering  the  plate,  the  brushing  need  not 
be  confined  to  only  the  four  directions.  Some  etch- 
ers apply  it  in  various  ways  until  the  lines  are  suf- 
ficiently protected.  No  powder  should  be  allowed 
to  remain  on  the  open  spaces,  and  to  prevent  ex- 
cessive shoulder  no  more  than  enough  to  protect 
the  lines  should  be  left  adhering  to  them.  How- 
ever, where  an  extra  strong  bite  is  to  be  given  it  is 
sometimes  well  to  powder  twice  around  the  plate. 
After  the  second  or  third  bite  the  small  spaces  will 


80  MANUAL   OF   PHOTO-ENGRAVING. 

fill  with  the  powder,  but  the  lines  being-  close 
tog-ether,  great  depth  is  not  required  as  in  the 
wider  spaces.  Should  any  of  the  powder  adhere 
to  the  open  spaces,  causing-  roug-hness,  a  knife  or 
scraper  can  be  used  to  clean  them.  After  the  fin- 
ishing- etch  has  been  given,  the  coating-  should  be 
removed  from  the  plate  by  scrubbing  with  lye,  and 
the  plate  delivered  to  the  router.  Alcohol  will  also 
remove  the  coating-,  but  is  more  expensive  than  lye. 


VIGNETTED    HALF-TONE  —  i  33-LINE    SCREEN. 
From  wash  drawing  by  J.  C.  Leyendecker. 


By  courtesy  Northern  Trust  Company,  Chicago. 


MANUAL   OF   PHOTO-ENGRAVING.  81 


CHAPTER   X. 
ETCHING  —  HALF-TONE   WORK. 

THE   ENAMEL   PROCESS. 

SENSITIZING    SOLUTION.  . 

A. —  Albumen  from  fresh  eggs 5  ounces  ^--  2. 

Water 2  ounces    / 

B. —  Bichromate  ammonia 140  grains 

Water 2  ounces    —  / 

Ammonia a  few  drops  - — 

C. —  Le  Page's  liquid  glue 5  ounces 

Water 3  to  4  ounces. /  -^_  —  ■2- 

Beat  up  the  eggs  with  the  water,  then  add  the 
solutions  B  and  C,  and  mix  all  together  thoroughly. 
The  solution  must  then  be  filtered  several  times 
through  sponge  or  absorbent  cotton  until  free  from 
specks  and  bubbles.  Make  also  a  solution  of  eosine 
(red  shade)  by  dissolving  some  of  the  powder  in 
hot  water  and  keep  in  a  tray  for  use. 

MANIPULATIONS. 

Have  the  copper  polished  and  the  surface  hold- 
ing a  film  of  water,  take  it  to  the  darkroom,  drain 
off  the  water  and  flow  the  plate  with  some  of  the 
enamel  solution,  draining  the  surplus  off  at  one 
corner,  then  flow  once  or  twice  again  and  drain, 
removing  any  specks  or  bubbles  with  a  small 
brush  or  stick.  Having  the  solution  clean  on  the 
plate,  put  it  in  the  whirler  face  down,  having  one 


82  MANUAL    OF    PHOTO-ENGRAVING. 

corner  in  the  opening-  in  one  of  the  clamps  and  the 
opposite  corner  in  the  opening-  of  the  other,  the 
clamps  being  so  placed  that  the  plate  will  be  cen- 
tered. Then  turn  the  hand  wheel  of  the  drill  so 
that  the  plate  will  be  given  a  rapid  whirling  motion 
which  will  spread  the  solution  evenly  over  the  sur- 
face. The  gas  stove  under  the  whirler  should  be 
burning  so  as  to  warm  the  plate  and  dry  the  coat- 
ing. The  plate  need  not  be  heated  excessively. 
Enough  to  dry  it  will  be  sufficient.  If  it  is  not 
convenient  to  have  a  stove  under  the  whirler,  the 
plate  may  be  whirled  cold  until  the  solution  is 
partially  dried,  and  then  removed  from  the  whirler 
and  heated  to  dry. 

If  the  coating  upon  examination  now  appears 
clean  upon  the  plate,  let  the  plate  remain  in  the 
dark  until  cold,  and  then  expose  under  a  half-tone 
negative  as  directed  for  exposing  line  plates. 
When  it  is  considered  as  sufficiently  printed,  re- 
move it  from  the  frame,  place  in  the  solution  of 
eosine  for  a  moment,  then  wash  under  the  tap. 
The  image  will  appear  of  a  brilliant  red  color,  and 
should  be  washed  until  the  details  are  all  clear. 
The  eosine  solution  is  simply  to  color  the  image  to 
render  it  clearly  visible  during  development.  Some 
etchers  omit  it,  but  its  use  enables  the  development 
of  the  details  to  be  more  readily  watched.  If  the 
plate  has  been  properly  exposed  the  dots  and  lines 
of  the  image  will  correspond  with  the  clear  spaces 
in  the  negative,  and  if  the  negative  is  one  of  good 
quality,  the  details  will  be  open  and  the  high  lights 
will  be  clear  with  dots  strong"  enough  to  allow  the 


MANUAL   OF    PHOTO-ENGRAVING.  83 

proper  depth  of  etch.  These  dots  should  be 
square  and  may  be  separate  from  each  other,  or 
just  touching-  at  the  corners,  but  the  union  should 
not  be  so  strong-  as  to  prevent  the  separation  of 
the  dots  in  etching,  for  the  best  effects  are  obtained 
when  the  high  lights  are  composed  of  separate 
stipple.  If  formed  of  lines  the  proofs  will  be  too 
dark.  If  the  print  has  been  over-exposed,  the 
details  will  be  filled  and  the  dots  in  the  whites  will 
probably  run  into  heavy  lines.  If  under-exposed, 
the  dots  in  the  whites  will  be  too  small  to  stand  the 
etching,  and  some  will  perhaps  be  washed  away  in 
developing,  while  the  image  will  be  weak.  When  a"" 
properly  exposed  print  has  been  obtained  and 
developed  it  should  be  flowed  several  times,  after 
being  taken  from  the  tap,  with  grain  or  wood 
alcohol  to  remove  the  water,  and  then  dried  spon- 
taneously, or  the  alcohol  may  be  ignited  and 
burned  off. 

The  print  must  then  be  burned  in,  which  is 
done  by  holding  the  plate  by  means  of  a  pair  of 
pincers  over  a  strong,  steady  heat,  until  the  coat- 
ing becomes  of  a  chocolate  brown  or  black  color. 
Then  let  cool  and  rub  with  a  dilute  solution  of 
chromic  acid,  which  will  clean  the  copper  and 
enable  any  spots  to  be  readily  detected.  The  plate 
must  now  be  spotted,  that  is,  any  stipple  which  is 
missing  must  be  replaced  by  some  substance  which 
resists  the  etching  fluid.  Either  asphalt  or  the 
transfer  ink  may  be  used  for  this  purpose.  A 
small  camel's-hair  brush  should  be  obtained,  and 
some  of  the  asphalt  being  placed  upon  it,  the  brush 
8 


84  MANUAL    OF    PHOTO-ENGRAVING. 

is  drawn  to  a  point  and  touched  to  the  spots  from 
which  the  stipple  is  missing,  and  also  any  portions 
of  the  image  which  it  is  desired  shall  appear  solid 
black  are  painted  in.  If  the  ink  is  used,  the  plate 
is  powdered  with  dragon's  blood,  which  is  brushed 
off  with  cotton,  the  plate  then  heated  enough  to 
burn  in  the  powder  adhering  to  the  spots  of  ink. 
The  back  is  then  painted  with  asphalt  varnish,  and 
the  plate  cooled.     It  is  then  ready  to  etch. 

For  the  etching  fluid  prepare  a  strong  solution 
of  perchloride  of  iron,  place  it  in  a  tray,  immerse 
the  plate  in  it  and  brush  the  face  of  the  plate  with 
the  etching  brush.  The  plate  can  now  be  allowed 
to  rest  in  the  solution,  being  brushed  occasionally 
to  clean  the  face  from  the  sediment  which  results 
from  the  chemical  action.  The  tray  may,  if  de- 
sired, be  rocked,  but  this  is  not  necessary.  Exam- 
ine the  plate  at  intervals,  and  when  the  dots  in  the 
high  lights  appear  to  have  had  as  much  etching  as 
they  will  stand,  brush  the  plate  and  wash  immedi- 
ately under  the  tap.  If  upon  further  examination 
the  dots  appear  large  enough  to  stand  more, 
return  the  plate  to  the  solution  and  continue  the 
etching.  When  finally  the  action  has  proceeded 
far  enough,  rinse  the  plate,  clean  with  solution  of 
chromic  acid,  rinse  again,  clean  the  asphalt  from 
the  back  with  turpentine,  dry  and  prove. 

ETCHING    VIGNETTES. 

Very  pretty  effects  can  often  be  obtained  by 
etching  a  vignette  or  blended  border  around  the 
image.     The  plate  is  first  etched  in  the  ordinary 


^Ffagf 


ZINC     ETCHING. 
From  pencil  and  pen  drawing-  by  Farny. 


Copyrighted. 


By  courtesy  The  Ault  &  Wiborg  Co.,  Cincinnati,  Ohio. 


MANUAL   OF    PHOTO-ENGRAVING.  85 

manner,  and  given  a  bite  deep  enough  for  printing-. 
It  is  then  dried  and  the  face  painted  in  solid  with 
the  asphalt  or  transfer  ink,  the  edge  of  the  paint 
not  being  carried  to  the  edge  of  the  plate,  so  that  a 
ground  of  stipple  is  left  around  the  painted  por- 
tion. The  plate  is  then  returned  to  the  etching 
solution  and  etched  a  few  moments  to  reduce  the 
stipple  in  size.  It  is  then  rinsed  and  dried  and 
painted  again,  the  paint  this  time  being  extended  a 
little  further.  Another  bite  is  then  given  to  reduce 
the  size  of  the  remaining  stipple,  and  the  opera- 
tions are  repeated.  When  the  desired  number  of 
tints  are  obtained,  the  plate  is  finally  etched  until 
the  remaining  border  of  stipple  is  broken  away. 
The  face  is  then  cleaned  with  turpentine  or  alcohol 
as  the  case  may  require,  and  the  edge  routed  and 
trimmed  with  the  hand  tool.  The  edges  of  the 
paint  should  be  wavy  and  may  require  a  little  artis- 
tic taste  to  produce  the  desired  effect.  A  proof 
from  such  a  plate  will  have  a  border  formed  of  a 
gradation  of  tints,  blending  from  dark  to  light.  It 
requires  some  practice  to  obtain  an  artistic  effect, 
as  the  edges  of  the  tints  must  not  be  too  pro- 
nounced. Three  or  four  and  even  as  many  as  five 
tints  may  be  obtained  by  skillful  etching. 

The  "Full  Tone"  or  "High  Light"  process  by 
which  plates  are  produced  with  certain  parts  of  the 
ground  free  from  stipple  is  done  by  simply  painting 
in  the  plate,  leaving  those  parts  unprotected,  then 
etching  until  the  stipple  breaks  away.  The  parts 
are  then  deepened,  and  finished  with  the  tool.  In 
printing,   to   bring   up   any   portion   of    the   plate 


86  MANUAL    OF    PHOTO-ENGRAVING. 

heavy,  shade  the  other  portions  after  they  have 
been  exposed  sufficiently,  and  allow  the  light  to  act 
longer  upon  that  part. 

In  etching-,  avoid  excessive  brushing".  Use  the 
brush  only  occasionally  to  clean  the  plate,  unless  it 
is  desired  to  etch  out  some  part  especially  light. 
To  obtain  a  better  idea  of  the  actual  depth  of  the 
etching  than  can  be  determined  by  the  appearance 
of  a  stipple,  scratch  off  with  a  knife  some  of  the 
enamel  on  the  margin  of  the  plate.  The  scratch 
will  etch  down  and  the  depth  can  be  felt  with  the 

X  finger  nail.  The  proportions  given  for  makings  v 
the  enamel  solution  are  not  arbitrary.  Different 
amounts  of  the  constituents  can  be  used  if  desired. 
An  excess  of  glue  will  cause  a  tendency  to  fill  in 
the  print,  while  a  solution  which  is  too  thin  will 
peel  from  the  plate  in  etching. 

Half-tone  etching  may  also  be  done  by  the  albu- 
men process,  using  the  same  solution  as  for  line 
work  which  is  generally  used  for  half-tones  on 
soft  zinc  which  will  not  stand  the  heat  in  burning 
in  the  enamel  solution. 


MANUAL   OF   PHOTO-ENGRAVING.  87 


CHAPTER   XI. 

FINISHING  AND   MOUNTING   PLATES. 

A  FTER  the  etching-  of  the  line  plate  is  finished  it 
/\  is  tacked  to  a  board  and  placed  in  the  routing- 
machine,  and  all  the  larger  open  spaces  deepened 
with  the  routing  tool.  If  several  negatives  have 
been  printed  on  one  sheet  of  zinc,  each  image  is  cut 
out,  a  thin  border  of  zinc  being  left  around  it.  The 
cut  is  then  fastened  to  a  block  by  tacks  driven 
through  the  routed  spaces  and  around  the  edge, 
and  the  block  planed  type-high.  Any  burr  remain- 
ing on  the  lines  is  then  removed  with  a  hand  tool, 
and  the  plate  is  ready  for  proving. 

In  mounting  a  half-tone  cut,  a  beveled  edge  may 
be  formed  around  the  cut  with  the  routing  or  bevel- 
ing machines,  and  the  plate  fastened  to  the  block 
by  tacks  driven  through  this  edge.  Another 
method  is  to  mount  the  plate  from  the  back  as 
follows :  Saw  the  margin  of  metal  from  around 
the  image,  leaving  enough"  for  a  black  line  (if  the 
line  is  wanted),  and  bevel  the  edge  with  a  file, 
removing  the  burr  from  both  sides.  Clean  the 
back  of  the  plate  and  scrape  the  surface  bright  in 
several  places,  leaving  several  deep  scratches  in  the 
places  thus  brightened,  then  upon  each  place  drop 
some    hydrochloric    acid,    and   lay  a    thin    piece  of 


88  MANUAL   OF   PHOTO-ENGRAVING. 

solder  upon  it.  Upon  the  solder  set  a  small  screw 
and  direct  the  flame  of  a  blowpipe  upon  the  solder 
until  it  melts  and  forms  around  the  head  of  the 
screw,  holding-  the  screw  in  position  by  any  conven- 
ient tool.  The  solder  should  not  be  too  large  or  it 
will  form  too  larg-e  a  mass  when  melted.  Having 
thus  soldered  screws  to  the  several  points,  which 
should  be  evenly  distributed  over  the  plate,  set  the 
plate  screws  down  upon  the  wood  block,  length  of 
the  plate  with  the  grain  of  the  wood,  lay  another 
block  upon  the  face  of  the  plate  and  strike  it  with 
the  hammer,  so  that  the  screw  will  leave  marks 
upon  the  face  of  the  first  block.  Then  with  a  one- 
fourth  inch  drill,  drill  holes  through  the  block  at 
these  points,  after  which  insert  a  countersink  drill 
in  the  chuck  and  with  it  drill  from  each  side  of  the 
block  into  the  holes  made  by  the  one-fourth  drill, 
letting  the  countersink  go  below  the  surface  of  the 
block  on  each  side.  Sandpaper  the  face  of  the 
block  and  place  the  plate  on  it  so  that  the  screws 
will  sink  into  the  corresponding  holes,  allowing  the 
plate  to  rest  flat  upon  the  surface  of  the  block. 
Then  protecting  the  face  of  the  plate  with  another 
block  clamp  it  tight,  and  with  a  small  ladle  pour 
melted  type  metal  into  the  holes  on  the  opposite 
side,  not  allowing  it  to  come  to  the  surface  of  the 
block.  When  it  is  cool  the  plate  will  be  firmly 
fastened  to  the  block. 

Saw  the  block  around  the  metal,  leaving  a  small 
margin  of  wood  and  then  it  is  ready  to  trim.  Place 
the  block  on  the  trimmer,  having  the  gauge  set  so 
that  the  knives  will  just  catch  one  edge,  and  pass 


HALF-TONE  — 150-LINE    SCREEN. 


MANUAL   OF    PHOTO-ENGRAVING.  89 

the  table  back  and  forth,  giving  the  gauge  screw  a 
slight  turn  each  time  until  the  wood  is  trimmed  up 
to  the  metal.  If  the  plate  is  so  placed  that  the 
wood  will  not  trim  parallel  to  the  edge  of  the  plate, 
place  a  piece  of  folded  paper  between  the  block 
and  gauge  to  cause  the  part  at  which  the  wood 
is  thickest  to  be  moved  farther  toward  the  knives. 
Trim  each  edge,  running  the  block  through  slowly 
when  making  the  last  cuts,  and  then  make  it  type- 
high  in  the  planer.  If  the  type  metal  should  be 
found  to  come  to  the  surface  of  the  block  it  should 
be  routed  down.  In  mounting  line  and  half-tone 
cuts  together,  if  the  plates  are  not  of  the  same 
thickness  the  thinner  ones  must  be  underlaid  to 
bring  their  surfaces  to  the  level  of  the  thickest 
plate.  Cherry  wood  is  usually  used  for  blocking 
plates,  metal  blocks  being  used  for  those  from 
which  stereotypes  are  to  be  made,  such  as  line 
plates  for  newspaper  work. 

The  first  proofs  from  half-tone  plates  will  often 
show  black  spots.  In  such  a  case  the  plate  is  given 
to  the  engraver  who  tools  them  out.  The  half-tone 
may  often  be  improved  also  by  having  certain  parts 
burnished  to  make  those  parts  in  the  proof  appear 
darker.  For  fine  magazine  work  it  has  become 
customary  to  use  the  tool  very  extensively  upon 
half-tone  plates,  many  of  them  being  given  the 
appearance  of  fine  wood  engravings.  The  tool  is 
also  often  used  to  vignette  portraits  and  to  clear 
away  the  stipple  in  places  where  it  is  desired  to 
have  clear  whites  in  the  proof. 


90  MANUAL  OF  PHOTO-ENGRAVING. 


CHAPTER   XII. 

DRAWINGS  —  PHOTO-LITHOGRAVURE. 

THE  line  drawing's  for  reproduction  should  be 
made  with  black  ink  and  the  lines  should  all 
be  sharp  and  bold.  Gray  and  fine  lines  are  ex- 
tremely difficult  to  reproduce,  especially  if  the 
reduction  is  great.  To  make  drawings  rapidly  and 
accurately,  a  common  "wrinkle"  is  to  draw  the 
lines  over  a  silver  print,  the  photographic  image 
being  afterwards  bleached  out,  leaving  the  draw- 
ing alone  on  the  paper. 

The  method  is  as  follows  :  Obtain  some  plain 
salted  paper  and  sensitize  it  by  brushing  over  the 
surface  a  tuft  of  absorbent  cotton  wet  with  a  solu- 
tion of  silver  nitrate.  Dry  in  the  dark  and  expose 
under  an  ordinary  negative  made  from  the  copy 
to  be  reproduced  until  the  image  shows  a  dark  red 
or  purple.  Wash,  then  place  in  a  dilute  solution 
of  acetic  acid  for  several  minutes  until  the  image 
is  fixed.  Wash  again,  then  dry  and  make  the 
drawing  over  it  with  Higgins'  waterproof  ink. 
When  this  is  dry,  flow  over  the  print  a  saturated 
solution  of  mercuric  chloride  in  alcohol,  or  in  about 
equal  parts  of  alcohol  and  water.  The  red  image 
will  be  removed,  leaving  the  drawing,  after  which 


MANUAL   OF    PHOTO-ENGRAVING.  91 

the  paper  should  be  rinsed  and  dried,  being-  then 
ready  for  the  photographer. 

Another  method  to  obtain  the  outlines  of  the 
drawing  is  to  make  a  ferrotype,  or  "tintype,"  and 
over  this  to  place  a  sheet  of  thin  transparent  gela- 
tine or  celluloid,  the  outlines  being  scratched  in 
with  a  point.  Powdered  graphite  or  other  pigment 
is  then  dusted  over  the  gelatine  and  adheres  to  the 
lines.  By  placing  the  gelatine  over  a  sheet  of 
paper,  line  side  down,  and  rubbing  it,  the  lines  will 
be  transferred  to  the  paper.  The  ferrotype  is 
made  in  the  same  manner  as  a  wet  plate,  the  sheet 
of  metal  being  substituted  for  the  glass. 

In  drawings  for  colorwork  it  is  often  desired  to 
have  the  part  of  the  drawing  for  each  color  made 
separate.  The  whole  drawing  is  first  made  in  the 
colors  as  they  are  to  appear  in  the  original,  then 
tissue  paper  is  placed  over  it  and  the  outlines  for 
one  color  drawn  upon  it.  The  back  of  the  paper  is 
then  covered  with  some  pigment  (rubbing  a  blue 
pencil  over  it  is  the  easiest  way),  laid  back  down  on 
another  piece  of  paper  or  card,  and  the  lines  traced 
over,  thus  transferring  them.  That  portion  of  the 
drawing  is  then  finished  up  as  desired  and  the 
others  obtained  in  a  similar  manner.  "Scratch 
board "  is  generally  used  for  making  drawings 
upon,  as  it  has  a  smooth  surface  with  no  grain  to 
appear  in  the  reproduction,  and  alterations  can  be 
made  upon  it  without  altering  the  character  of  the 
surface. 


92 


MANUAL    OF    PHOTO-ENGRAVING. 


MANUAL    OF    PHOTO-EXGK AYIXG.  93 

PHOTO-LITHOGRAVURE. 

Bv  the  term  photo-lithogravure,  as  used  here,  is 
meant  the  reproduction  of  line  drawings  containing 
tints  of  lines  or  dots. 

The  method  largely  used  for  placing-  these  tints 
upon  the  copy  is  known  as  the  Ben  Day  process. 

The  apparatus  consists  of  a  film  of  gelatine 
mounted  in  a  frame,  the  form  of  the  tints  being  so 
placed  in  relief  upon  it  that  when  rolled  up  with 
ink  they  can  be  readily  transferred  to  the  copy  by 
placing  the  film  above  it  and  pressing  upon  it  with  a 
burnisher  or  other  convenient  instrument.  Similar 
results,  however,  may  be  obtained  by  the  following 
method. 

The  necessary  apparatus  is  simply  several  plates 
ruled  to  form  tints  of  lines  or  dots,  some  examples 
of  which  are  shown. 


These  rulings  are  made  upon  plates  of  stereo- 
metal  mounted  on  blocks  of  wood  to  be  type  high. 
We  will  now  consider  the  application  of  the  method 
as  shown  in  the  example  (page  92).  First  there  was 
drawn  the  outline  of  the  letters  with  the  curves 
and  scrolls  forming-  the  skeleton  of  the  drawing. 


94  MANUAL   OF   PHOTO-ENGRAVING. 

The  tints  were  then  all  put  in  as  follows  :  Take  the 
dotted  tint  around  the  numbers  141,  143,  145,  which 
also  appears  at  the  upper  portion  of  the  plate  near 
the  name  Marvin.  A  sheet  of  smooth  tissue  paper 
was  tightly  stretched  over  the  face  of  the  drawing-, 
being-  pasted  around  three  edges.  Then  the  outline 
of  the  tint  was  drawn  with  a  pencil.  After  this 
was  done  a  card  was  slipped  under  the  tissue  and  the 
tissue  cut  out  with  a  sharp  knife  on  the  lines  just 
drawn,  the  card  being  then  removed,  leaving  the 
space  on  the  drawing  bare  where  the  tint  was  to  be 
placed.  The  drawing  was  then  placed  on  the  bed 
of  a  hand  press,  the  tint  block  rolled  up  with  ink 
and  placed  face  down  upon  it.  The  pressure  being 
then  brought  to  bear  leaves  the  dots  on  the  face  of 
the  drawing  in  the  open  space,  the  other  parts  of 
the  drawing  being  protected  by  the  tissue.  This 
sheet  of  tissue  being  then  removed  another  one  is 
put  on,  the  outlines  for  another  tint  drawn  and  cut 
out,  the  tint  block  being  rolled  up  and  the  impres- 
sion being  taken  as  before,  leaving  another  tint  on 
the  drawing,  and  so  on  for  the  remaining  tints. 

To  get  the  cross-line  tints,  two  impressions  are 
taken  from  a  single-lined  plate,  the  position  of  the 
plate  for  the  second  impression  being  at  right 
angles  to  the  first  position.  In  making  a  shade 
line  around  letters  where  it  is  desired  to  have  a 
white  space  between  the  letter  and  the  shading,  the 
tint  may  be  allowed  to  run  up  to  the  letter  when 
the  impression  is  made,  the  white  space  being 
scraped  out  afterwards.  When  letters  which  are 
to   appear  white    are    to   be    protected  while    the 


MANUAL   OF    PHOTOENGRAVING.  95 

impression  is  being-  made,  tissue  cut  out  to  fit  the 
letters  are  pasted  on  them  at  two  or  three  points, 
the  paste  being-  removed  afterwards.  When  the 
tints  are  all  inserted  in  the  drawings  the  reproduc- 
tion is  made  in  the  camera  as  usual.  This  process 
gives  results  similar  to  those  obtained  in  litho- 
graphing, and  very  handsome  effects  can  be 
obtained  by  running  the  tints  in  colors. 


'•Hi  MANUAL   OF    PHOTO-ENGRAVING. 


CHAPTER   XIII. 

DEVELOPMENT   OF   GELATINE   DRY 
PLATES. 

GENERAL    PRINCIPLES. 

IN  the  development  of  the  gelatine  dry  plates  the 
reduction  of  silver  to  form  the  image  is  ob- 
tained by  an  agent  which  decomposes  the  silver 
salts  affected  by  lig"ht.  Combined  with  this  ag-ent 
several  others  are  usually  used,  each  of  which  has 
a  special  influence  in  determining-  the  result. 

Besides  the  reducing  agent  we  will  have,  there- 
fore, the  following  components  in  the  solution.  An 
alkali,  usually  sodium  carbonate  (sal  soda).  The 
action  of  the  alkali  is  to  render  the  film  more  easily 
permeable,  and  to  increase  the  affinity  of  the 
reducing  agent  for  oxygen,  thus  increasing  its 
reductive  powers,  causing  the  reduction  to  take 
place  in  the  parts  least  affected  by  light  before 
great  density  has  been  obtained  in  the  high  lights. 
Detail  is  therefore  obtained  in  the  middle  tones, 
producing  an  image  full  of  gradation,  and  should 
the  proportion  of  alkali  be  too  great,  the  reduction 
of  the  silver  will  be  rapid,  and  take  place  over  the 
entire  surface,  causing  fog.     If  there  is  an  excess 


ZINC    ETCHING  — BLACK    AND    WHITE    EFFECT. 
Drawn  b}-  John  Sloan. 


MANUAL    OF    PHOTOENGRAVING.  97 

of  alkali,  yet  not  sufficient  to  cause  fog-,  the  details 
will  develop  too  rapidly  and  be  so  strong-  when  the 
proper  density  in  the  high  lights  has  been  reached, 
that  the  negative  will  be  too  flat  and  wanting  in 
contrast. 

To  prevent  the  reducing  agent  from  absorbing 
oxygen  from  the  air,  a  sulphite,  usually  sodium 
sulphite,  is  added  to  the  developer.  Having  a 
greater  affinity  for  oxygen  than  the  reducing 
agent,  it  takes  up  the  oxygen,  thus  preventing  the 
decomposition  of  the  reagent,  and  also  preventing 
stain. 

To  prevent  the  too  rapid  action  of  the  reagent 
and  to  preserve  clearness,  a  restrainer,  usually 
bromide  of  potassium,  is  used.  The  action  of  the 
restrainer  is  more  energetic  upon  the  middle  tones 
than  upon  the  high  lights,  and  when  by  over-ex- 
posure, or  excess  of  alkali,  these  portions  tend  to 
develop  too  rapidly,  it  is  used  to  retard  the  action 
until  the  high  lights  have  gained  in  intensity,  thus 
obtaining  contrast,  where  desired,  and  preventing 
fog  from  any  excess  of  alkali. 

An  excess  of  the  restrainer  acts,  therefore,  like 
an  excess  of  the  reducing  agent  to  produce  hard-' 
ness  and  contrasts. 

It  is  evident  that  we  may  mix  the  developer  in 
proportions  to  promote  detail  or  contrasts,  or  that 
we  may  manipulate  it  so  that  one  constituent  will 
retard  the  action  of  another  to  any  desired  extent. 
There  are  certain  proportions,  however,  of  the 
constituents  entering  into  the  composition  which 
may  make  what  we  may  term  a  normal  developer, 


98  MANUAL   OF    PHOTO-ENGRAVING. 

that  is,  a  developer  which  when  applied  to  a  prop- 
erly exposed  plate  will  bring-  out  the  gradations 
and  intensity  in  proper  order,  producing-  a  negative 
of  the  best  technical  quality. 

As  stated  in  a  preceding  chapter,  the  time  of 
exposure  is  a  matter  of  no  less  importance  than  the 
development  of  the  negative,  for  while  with  skillful 
manipulation  good  results  may  be  obtained  from 
the  plate  slightly  under  or  over  exposed,  it  is  only 
with  correct  exposure  that  the  best  effects  are 
produced. 

The  exposure  time  of  the  gelatine  plate  is  much 
shorter  than  for  the  collodion,  varying  from  a  small 
fraction  of  a  second  to  several  seconds  (or  perhaps 
under  special  conditions  to  an  extended  time  i. 

A  correct  exposure  properly  developed  will  yield 
a  negative  having  gradations  to  render  the  details 
in  the  subject,  but  will  preserve  the  contrasts  suffi- 
ciently to  avoid  flatness  in  the  resulting  print. 

Over-exposure  tends  to  produce  negatives  full  of 
detail,  yielding  prints  without  brilliancy. 

Under-exposure  tends  to  produce  negatives  with 
strong  contrasts,  lacking  in  detail,  the  resulting 
print  being  hard. 

The  treatment  for  over  or  under  exposed  plates 
will  be  given  below. 

Various  reducing  agents  may  be  used  in  the 
development  of  gelatine  plates,  but  pyrogallol  is 
considered  the  standard  by  the  majority  of  profes- 
sional photographers. 


MANUAL    OF    PHOTO-ENGRAVING.  99 


PYRO    DEVELOPER. 

Prepare  stock  solutions  as  follows  : 

A. — Sodium  sulphite,  40  by  actino-h3rdrometer  ;  and 

B. — Sal  soda,  20  b3r  actino-hydrometer. 

C. — Bromide  of  potassium,  1  part  to  9  or  10  parts  water. 

For  convenience  these  solutions  may  be  made  up 
in  quantities. 

To  prepare  the  developer,  take  one  part  ot  the 
sulphite  solution  A,  one  part  of  the  alkaline  solution 
B,  and  two  parts  of  water,  then  add  21/i  grains  of 
pyro  for  each  ounce  of  the  resulting-  solution.  Then 
add  a  few  drops  of  the  bromide  solution  C. 

In  cold  weather  enougri  heat  may  be  applied  to 
the  water  to  just  remove  the  chill,  but  it  must  not 
be  warm. 

In  hot  weather  increase  the  proportion  of  water 
to  2) 2  or  3  parts,  and  keep  the  solution  cold  by 
placing-  ice  in  it. 

FIXING    BATH   (CRAMER). 

A. — Water 1  quart 

Sulphite  soda 4  ounces 

Sulphuric  acid l/2  ounce 

Chrome  alum 3  ounces 

B.^Water 3  quarts 

Hyposulphite  soda 32  ounces 

Dissolve  A  and  B  separately  and  mix.  In  cold 
weather  use  one-half  the  quantity  of  A. 

DEVELOPMENT. 

In  the  development  of  the  plate,  the  points  to  be 
considered  are  :    First,  the  time  in  which  the  imag-e 


100  MANUAL   OF    PHOTO-ENGRAVING. 

appears  ;  second,  the  contrasts  ;  third,  the  detail ; 
fourth,  the  intensity.  An  intellig-ent  judgment  of 
these  will  enable  the  operator  to  determine  whether 
the  exposure  has  been  of  the  proper  duration,  and 
conduct  the  development  accordingly. 

Place  the  plates  in  a  clean  tray,  which  should  be 
kept  for  this  purpose  alone,  and  flow  the  developer 
over  them  in  an  even  wave,  using-  enough  to  cover 
the  plates.  Then  rock  the  tray  to  cause  the  de- 
veloper to  flow  from  side  to  side.  If  the  exposure 
has  been  properly  timed  the  high  lights  of  the 
image  will  appear  first,  then  the  gradations  in  the 
middle  tones,  those  corresponding  to  the  lighter 
shades  first,  being  followed  by  the  darker  shades, 
then  the  details  in  the  shadows.  When  all  the 
gradations  have  thus  appeared  in  proper  order, 
the  development  is  continued  until  the  proper 
intensity  is  reached,  which  is  determined  by  the 
appearance  of  the  plate  when  held  up  to  the  red 
light.  Only  experience  will  enable  the  intensity 
to  be  properly  judged.  Some  papers  will  require 
a  denser  negative  than  others. 

If  the  exposure  time  has  been  too  short,  the 
imag-e  will  be  late  in  appearing  as  compared  to 
the  normal,  and  the  details  in  the  half-tones  and 
shadows  will  hang  back,  and  if  the  development  is 
carried  on  as  for  proper  exposures  the  high  lights 
will  gain  the  desired  intensity  before  the  details 
will  come  out,  thus  producing  a  hard  negative 
devoid  of  detail.  In  such  a  case  simply  place  the 
plate  in  a  tray  containing  developer  diluted  with 
water.      The    development   will    then    take   place 


VIGNETTED    HALF-TONE,   HIGH-LIGHT    EFFECT  —  100-LINE    SCREEN. 
From  wash  drawing-  by  W.  L.  Wells. 


MANUAL    OF    PHOTO-ENGRAVING.  101 

slowly,  the  details  having-  time  to  appear  before 
the  high  lights  assume  any  great  intensity. 

When  the  details  have  properly  appeared,  the 
plate  can,  if  necessary,  be  returned  to  the  normal 
developer  until  the  proper  intensity  is  obtained. 

Some  operators  place  under-timed  plates  in  a 
developer  to  which  an  excess  of  alkali  has  been 
added,  but  such  forcing  of  detail  will  seldom  yield  a 
good  negative,  and  there  is  great  liability  to  fog. 

If  there  is  any  detail  which  can  be  brought  out 
the  method  given  above  will  do  it.  A  badly  under- 
timed  plate  will,  of  course,  never  produce  a  good 
negative. 

If  the  plate  has  been  over-exposed,  the  image 
rapidly  appears,  the  details  coming  up  with  the 
high  lights,  and  the  negative  will  be  flat.  In  such 
a  case  it  should  be  placed  in  a  tray  containing  nor- 
mal developer  to  which  there  has  been  added  more 
of  the  bromide  solution.  The  restrainer  will  cause 
the  reduction  in  the  portions  least  affected  by  the 
light  to  be  retarded,  while  the  high  lights  will  gain 
in  intensity,  thus  producing  contrasts. 

When  a  number  of  plates  are  developed  in  suc- 
cession the  developer  will  deteriorate,  and  should 
be  replaced  by  fresh  as  occasion  may  demand. 

During  development,  the  plate  should  be  exam- 
ined from  time  to  time  by  holding  it  between  the 
eye  and  the  red  light,  and  when  the  proper  inten- 
sity has  been  obtained  it  should  be  rinsed  for  a 
moment  under  the  tap  and  placed  in  the  fixing  bath, 
in  which  it  should  remain  for  five  or  ten  minutes 
after  the  white  color  has  left  the  film. 


102  MANUAL    OF    PHOTO-ENGRAVING. 

After  fixing-,  it  should  be  washed  in  running- 
water  for  at  least  two  hours  to  remove  the  hypo 
from  the  film. 

When  taken  from  the  water,  the  ball  of  the 
hand  may  be  passed  over  the  face  of  the  negative 
to  remove  any  sediment  from  the  water,  the  plate 
being  then  placed  in  the  rack  to  dry. 

Instead  of  using  dry  pyro,  it  is  customary  with 
many  operators  to  have  a  pyro  solution,  various 
formulae  being  given  by  platemakers.  The  above 
formula?  with  dry  pyro,  however,  will  give  results 
second  to  none. 

A  number  of  other  reducing  agents  are  on  the 
market,  some  of  which  dispense  with  the  use  of  an 
alkali,  but  for  all-around  work  with  all  brands  of 
plates  pyro  continues  as  a  standard. 

Among  the  other  agents  which  have  gained  in 
favor  metol  is  one  of  the  best,  giving  excellent 
results.  This  developer  may  be  prepared  as  fol- 
lows : 

Make  stock  solutions  of  sal  soda  at  30,  and  sul- 
phite at  60  by  the  hydrometer. 

Take  20  ounces  of  each  and  add  to  it  40  ounces 
of  water  in  which  y?  ounce  of  metol  has  been  dis- 
solved. 

In  warm  weather  dilute  with  an  equal  quantity 
of  water. 

The  manipulation  is  the  same  as  with  pyro. 

INTENSIFICATION. 

If  the  development  of  the  negative  has  not  been 
carried    far    enough    it   will    be    thin    and    require 


MANUAL    OF    PHOTO-ENGRAVING.  103 

intensification.  Various  formula?  may  be  used,  but 
those  containing  mercury  are  commonly  employed. 

Dissolve  2*2  ounces  of  iodide  of  potassium  in  12 
ounces  of  water  and  pour  into  it  gradually  a  satu- 
rated solution  of  bichloride  of  mercury.  A  red  pre- 
cipitate of  mercuric  iodide  will  be  formed.  The 
mercury  solution  must  be  added  until  this  precipi- 
tate cannot  be  dissolved  by  shaking-.  Avoid  adding 
any  more  mercury,  however,  than  will  make  the 
solution  very  slightly  turbid.  Then  add  2Jj  ounces 
hyposulphite  of  soda,  and  when  dissolved  add  water 
to  make  up  to  40  ounces. 

For  use,  take  one  part  of  the  above  solution  to 
three  parts  of  water  and  immerse  the  negative 
after  fixing  and  washing  until  sufficient  density  is 
obtained.  If  the  hypo  has  not  been  thoroughly 
washed  from  the  film,  the  intensifier  will  cause 
stains.  If  over-intensified  the  density  may  be 
reduced  by  leaving  the  negative  in  the  fixing  bath 
for  a  short  time. 

REDUCTION. 

Negatives  which  are  too  dense  may  be  reduced 
by  a  dilute  solution  of  hypo  to  which  a  little  of  a 
solution  of  potassium  ferricyanide  has  been  added. 

The  solutions  may  be  made  up  of  }4  ounce  of 
the  salt  to  8  ounces  of  water.  Add  a  little  of  the 
potassium  solution  to  the  hypo  solution  and  im- 
merse the  negative  until  sufficiently  reduced,  then 
remove  and  wash. 


104  MANUAL   OF    PHOTO-ENGRAVING. 

CAUSES   OF   DEFECTS    IN    GELATINE    NEGATIVES. 

Fog. — White  light  entering-  darkroom  or  cam- 
era, over-exposure,  excess  of  alkali  in  developer, 
hypo  or  other  chemicals  in  developer,  developer  too 
warm. 

Negative  too  thin. — If  the  shadows  lack  detail, 
under-development  ;  if  the  shadows  have  detail, 
weak  developer,  or  exposure  too  great. 

In  tensity  too  great. — Over-development,  reagent 
in  excess  in  developer,  or  warm  developer. 

Abnormal  contrasts. — Under-exposure  or  devel- 
oper too  strong. 

Frilling. — Solutions  too  warm,  insufficient  alum 
in  fixing  bath  or  prolonged  washing-. 

Flatness. — Over-exposure  or  too  much  alkali  in 
developer. 

Spots. — Dust  or  bubbles  in  developer. 

Stains. — Developer  oxidized,  impure  chemicals 
or  not  enough  sulphite  in  developer,  deteriorated 
fixing  solution  or  insufficient  fixing. 

Streaks. — Developer  allowed  to  flow  unevenly 
over  plate  when  first  applied,  or  fixing  bath  acid. 

Crystals  on  negative. — Hypo  not  all  removed 
frjm  film. 


ZINC    ETCHING    OF    PORTRAIT— MEDALLION  EFFECT. 
From  drawing  by  Jules  M.  Gaspare! . 


MANUAL   OF    PHOTO-ENGRAVING.  103 


CHAPTER    XIV. 

ORTHOCHROMATIC   PLATES  —  COLOR 
WORK. 

COLOR. 

THE  undulatory  theory  of  light,  which  is  now 
accepted  as  explaining-  most  satisfactorily  its 
various  phenomena,  assumes  that  light  is  produced 
by  vibrations  of  the  ether,  an  imponderable,  color- 
less, perfectly  elastic  fluid  which  is  supposed  to  pen- 
etrate all  matter  and  occupy  all  space.  The  waves 
of  ether,  being-  generated  by  the  source  of  light, 
are  transmitted  from  it  in  all  directions,  the  vibra- 
tions being  transverse  to  the  direction  in  which  the 
ray  of  light  is  moving. 

The  sensation  of  white  light  is  not  caused  by 
one  set  of  vibrations,  but  by  several,  for  if  we  pass 
a  ray  of  white  light  through  a  prism  it  will  be 
decomposed,  and  the  result  will  be  a  series  of  colors 
(the  spectrum)  which  can  be  shown  upon  a  screen, 
each  pure  color  being  produced  by  ethereal  waves 
always  of  the  same  length  but  differing  in  length 
from  the  waves  which  produce  any  of  the  other 
colors.  This  decomposition  of  the  white  light  is 
caused  by  the  refraction  or  bending  of  the  rays  as 
they  pass  through  the  prism,  each  of  the  compo- 
nent rays  being  bent  at  a  different  angle  than  any 
10 


106  MANUAL   OF    PHOTO-ENGRAVING. 

of  the  others.  The  waves  which  are  the  longest 
and  which  produce  the  red  sensation  are  refracted 
least,  and  the  shortest  waves  —  those  which  produce 
the  violet  sensation  —  are  refracted  most,  the  waves 
producing-  the  intermediate  colors  being-  refracted 
more  or  less  according  to  their  relative  lengths. 
Besides  the  rays  of  the  spectrum  which  affect  the 
eye,  others  exist  which  are  not  visible  and  which 
can  be  detected  by  their  chemical  effect. 

Pure  colors  —  that  is,  colors  which  are  produced 
by  only  one  set  of  vibrations  —  are  to  be  found  only 
as  spectral  colors.  They  cannot  be  obtained  from 
any  pigment,  for  no  matter  how  nearly  any  pig- 
ment may  appear  optically  to  approach  a  color  of 
the  spectrum,  spectroscopic  analysis  will  show  its 
color  to  be  produced  by  more  than  one  set  of  vibra- 
tions. 

The  red,  green  and  blue-violet  of  the  spectrum 
are  the  fewest  pure  colors  from  which  by  combina- 
tion in  certain  proportions  of  two  or  the  three  any 
other  color  may  be  produced,  and  they  are  there- 
fore termed  primary  colors.  The  sensation  of 
yellow,  for  instance,  may  be  obtained  by  the  com- 
bined action  of  the  pure  red  and  green  rays,  purple 
of  red  and  blue  or  violet,  while  white  light  is  pro- 
duced by  the  combination  in  equal  quantities  of  all 
three  primary  rays.  The  proportions  may  be 
varied  to  produce  other  colors.  Lilac  may  be  pro- 
duced by  the  combination  of  blue  and  red,  the  blue 
rays  predominating,  while  orange  may  be  obtained 
by  combining  red  and  green,  the  red  predominat- 
ing. 


MANUAL   OF   PHOTO-ENGRAVING.  107 

The  color  of  any  object  (or  pigment)  depends 
upon  its  properties  of  absorption  or  reflection  of 
the  primary  rays.  If  illuminated  by  white  light 
and  all  the  rays  are  reflected,  it  is  said  to  be  white. 
If  all  the  rays  are  absorbed,  it  is  said  to  be  black, 
and  if  some  are  absorbed  and  some  reflected  the 
color  will  be  determined  by  the  reflected  rays  ;  for 
example,  if  the  green  and  blue-violet  rays  are 
absorbed  and  the  red  reflected,  the  object  is  said  to 
be  red.  Some  objects,  such  as  colored  glass  or 
colored  solutions,  allow  some  rays  to  pass  through 
them,  absorbing  or  reflecting  others,  and  this  prop- 
erty is  utilized  in  filtering  out  certain  rays  which 
it  is  desired  shall  act  upon  the  sensitive  plate  to 
obtain  certain  results. 

Two  colors  which  combined  produce  white  are 
called  complementary  colors.  Since  the  three  pri- 
mary colors  combined  produce  white,  it  follows  that 
the  color  resulting  from  the  combination  of  any 
two  of  them  is  complementary  to  the  other  pri- 
mary. Primary  red  and  green  give  the  sensation 
of  yellow,  which  is  therefore  complementary  to  the 
primary  blue. 

ORTHOCHROMATIC    PLATES. 

If  a  negative  is  made  from  a  colored  object  by 
using  an  ordinary  photographic  plate,  it  will  be 
found  that  the  true  color  values  have  not  been 
obtained  in  the  negative  —  that  is,  the  reds  and 
yellows  will  appear  too  dark  in  comparison  with 
their  values  in   the   original,   while  the  blue  will 


108  MANUAL    OF    PHOTO-ENGRAVING. 

appear  as  white.*  This  is  due  to  the  fact  that  the 
only  visible  rays  of  the  spectrum  which  affect  the 
ordinary  plate  are  the  blue-violet  rays,  these  being 
the  only  rays  absorbed  (except  the  invisible  rays 
from  beyond  the  violet,  which  are  known  as  the 
ultra-violet  rays). 

This  defect  in  the  plate  may  be  remedied,  how- 
ever, by  treating-  the  film  with  certain  dyes  which 
may  be  added  to  the  emulsion  before  the  plate  is 
coated,  or  the  coated  plate  may  be  bathed  in  a  solu- 
tion of  the  dye.  If  a  plate  thus  prepared  is  exposed 
to  a  colored  object,  a  transparent  yellow  filter  of  the 
proper  intensity  being-  so  placed  that  the  light  will 
pass  through  it  before  acting-  upon  the  plate,  the 
resulting-  negative  will  show  practically  the  true 
color  values,  the  blacks,  reds  and  blues  appearing 
as  dark  parts  in  proportion  to  their  relative  inten- 
sities, while  the  yellows  will  appear  as  light  parts. 

The  use  of  the  yellow  filter  is  to  cut  off  the 
action  of  the  blue-violet  rays  to  which  the  plate,  of 
course,  remains  sensitive. 

Such  a  negative  is  called  orthochromatic,  from 
the  Greek  words  meaning  correct  and  color. 

COLOR    PLATES. 

Instead  of  sensitizing  and  exposing  the  plate  to 
obtain  the  effect  of  all  the  colors,  it  may  be  ren- 
dered sensitive  to  certain  rays  and  others  excluded 

*  The  effect  of  a  pure  red  or  yellow  would  be  practically  the  same  as 
black.  That  red  and  yellow  pigments  will  usually  have  some  action  on  the 
plate  is  due  to  the  fact  that  they  reflect  more  or  less  blue-violet  —  no  pig-men t, 
as  stated  before;  having1  a  pure  color. 


VIGNETTED     HALF-TONE  —133-LINE    SCREEN. 
With  tint  background. 


MANUAL   OF   PHOTO-ENGRAVING.  109 

during-  exposure  by  means  of  a  properly  dyed  color 
filter.  We  can  then  make  from  any  colored  object 
three  negatives,  one  of  which  shall  have  been 
affected  by  the  red  rays,  one  by  the  green  and  one 
by  the  blue-violet.  If,  then,  three  printing  plates 
are  made  corresponding  to  these  negatives  and 
printed  in  pigments  of  complementary  colors,  the 
images  being  properly  superposed,  the  result  will 
be  a  reproduction  in  the  colors  of  the  original. 
Inks  complementary  in  color  are  used  because,  to 
produce  the  desired  effect,  there  must  be  absorbed 
from  the  white  paper  such  primary  rays  as  the 
original  absorbed  from  the  white  light  which  illu- 
minated it,  which  will  cause  the  proper  rays  to  be 
reflected  to  reproduce  the  colors  of  the  original. 
The  quantity  of  the  respective  colors  reflected 
from  the  image  will  be  equal  in  quantity  to  those 
reflected  from  the  original  when  the  quantity 
absorbed  by  the  pigments  from  the  white:  ground 
is  equal  to  the  quantity  absorbed  from  the  light  by 
the  original. 

Blue  of  the  proper  shade  will  absorb  red,  red 
will  absorb  green,  and  yellow  will  absorb  blue. 
The  printing  plate  corresponding  to  the  "  red  neg- 
ative "  must  be  printed  in  blue,  to  the  "green 
negative"  in  red,  and  to  the  "blue  negative"  in 
yellow. 

The  inks  must,  of  course,  be  sufficiently  trans- 
parent to  allow  the  passage  of  the  proper  rays.* 


*  Discrimination  must,  of  course,  be  used  in  the  selection  of  inks  of  the 
proper  shades.  Of  two  pigments,  for  instance,  both  may  be  said  to  be  blue, 
and  one  have  much  greater  red-absorbing  properties  than  the  other. 


110  MANUAL   OF   PHOTO-ENGRAVING. 

To  obtain  any  one  of  these  negatives  the  coat- 
ing of  the  plate  must  be  sensitive  to  those  rays  bv 
which  it  is  to  be  affected,  and  the  other  rays  to 
which  it  will  also  be  sensitive  must  be  excluded  bv 
means  of  a  color  filter. 

For  the  "blue-violet  negative,"  corresponding 
to  the  yellow-printing  plate,  an  ordinary  gelatino- 
bromide  plate  may  be  used  with  a  methyl  violet 
filter,  which  will  prevent  the  action  of  the  ultra- 
violet rays  which  would  interfere  wTith  the  ren- 
dering of  the  true  color  values. 

For  the  "green  negative"  (red-printing  plate), 
the  orthochromatic  (erythrosine-cyanine)  plates  as 
prepared  by  dry-plate  makers  may  be  used  with  a 
strong  yellow  filter,  which  will  allow  the  green 
rays  to  pass  and  cut  out  the  blue-violet. 

The  "red  negative"  (blue-printing  plate  >  may 
be  made  with  an  ordinary  plate  treated  with 
cyanine,  which  renders  the  plate  sensitive  to  all 
rays  except  green.  The  cyanine  solution  may  be 
made  by  dissolving  ten  grains  cyanine  C.  P.  in 
twenty  ounces  alcohol.  The  plate  is  dipped  in  this 
for  twenty  or  thirty  seconds,  rinsed  in  distilled 
water,  and  dried  in  the  dark.  Any  filter  may  be 
used  which  will  exclude  blue-violet  rays  and  admit 
the  red.     Crysoidine  orange  will  give  good  results. 

Plates  sensitized  with  cyanine  are  extremely 
liable  to  fog  and  must  be  developed  in  almost 
darkness. 

In  making  any  of  the  color  negatives,  exposure 
and  development  must  be  correct  or  the  color  values 
will  not  be  rendered  properly. 


MANUAL   OF    PHOTO-ENGRAVING.  HI 

The  color  filters  must  be  correct,  and  their 
qualities  should  be  determined  by  examination  with 
the  spectroscope,  which  shows  the  colors  transmit- 
ted. They  may  be  made  by  coloring-  collodion  or 
gelatine  and  coating-  glass  with  it,  or  by  placing  a 
colored  solution  in  a  glass  cell.  The  glass  plates 
must  have  their  sides  parallel  and  free  from  irreg- 
ularities or  a  blurred  image  will  result.  The  color 
screen  may  be  placed  in  front  of  the  lens  or  at  the 
back,  the  latter  position  being  generally  preferred. 

Having  obtained  the  three  negatives,  the  next 
step  is  to  make  from  them  three  corresponding 
positives,  which  may  be  made  on  either  gelatine  or 
collodion  plates,  care  being  taken  to  not  make  the 
positives  too  intense. 

During  the  operations  of  making  the  negatives 
and  also  the  positives  the  camera  must  be  firmly 
fastened  that  no  movement  whatever  shall  occur, 
for  the  slightest  variation  will  render  useless 
results. 

The  positives  must  now  be  placed  so  that  the 
half-tone  negatives  for  the  printing  plates  can  be 
made  from  them  by  transmitted  light,  the  camera 
as  before  being  fixed  to  avoid  any  movement.  The 
form  of  the  diaphragm  aperture  is  an  important 
consideration  in  making  these  negatives.  If  the 
round  or  square  aperture,  such  as  used  for  ordi- 
nary work,  be  employed,  it  is  evident  that  the 
superposition  of  the  -images  from  the  printing 
plates  would  result  in  a  moire  effect ;  but  if  aper- 
tures of  such  a  form  be  employed  as  will  give  in 
each  case,   an  effect,   not  of  cross  lines,  but  of  a 


112  MANUAL   OF   PHOTO-ENGRAVING. 

single  set  of  parallel  lines  which  when  superposed 
will  cross  the  lines  of  the  other  images  at  the 
proper  angle,  the  moire  effect  will  be  avoided.  In  a 
preceding  chapter  it  was  stated  that  the  form  of 
aperture  determined  the  shape  of  the  dot  in  the 
negative.  If  a  slot-shaped  aperture  is  used,  its 
sides  being  parallel  to  one  of  the  sets  of  lines  of  the 
screen,  the  resulting  negative  will  be  made  up  of 
continuous  lines  running  in  one  direction,  due  to  the 
joining-  of  the  images  of  the  aperture  ;  but  if  the 
aperture  be  broadened  in  the  middle  so  as  to  have 
an  elliptical  form,  the  negative  will  be  made  up 
of  similarly  shaped  dots  in  the  lighter  portions, 
the  dots  being  ranged  in  parallel  lines  and  joining 
to  form  solid  lines  in  the  shadows.  With  the  use 
of  properly  shaped  apertures  in  the  diaphragms 
we  have  a  means,  therefore,  for  obtaining  proper 
effects  with  a  cross-line  screen. 

To  cause  the  lines  of  the  negative  to  run  at  the 
desired  angle  in  each  case,  the  kit  for  holding  the 
positives  may  be  arranged  to  revolve  through  any 
number  of  degrees  as  required.  The  positives  are 
then  placed  successively  in  the  kit  and  turned  as 
required  to  sixty  degrees  for  the  exposure.  If  the 
positives  are  properly  placed  as  regards  right  and 
left,  it  will  not,  of  course,  be  necessary  to  reverse 
the  negatives. 

An  examination  of  the  color  plates  will  show 
the  forms  of  the  elements  and  their  proper  relation 
to  each  other. 

The  operations  should  be  so  carried  out  that  the 
printing  plates  shall  have  quite  open  high  lights, 


ZINC    ETCHING— WITH     GRAIN     EFFECT. 
Drawn  by  Fred  Richardson. 


MANUAL    OF   PHOTO-ENGRAVING.  113 

any  parts  which  are  desired  to  appear  extra  light 
being-  corrected  with  the  tool.  Perfect  register  is 
essential  in  printing  these  plates  to  obtain  correct 
results.  The  yellow  is  printed  first,  the  red  super- 
posed next,  and  the  blue  last.  Plates  mounted  on 
metal  bases  give  much  better  results  in  printing 
than  if  mounted  on  wood. 


11-1  MANUAL   OF   PHOTO-ENGRAVING. 


CHAPTER   XV. 

PRINTING   HALF-TONE   PLATES. 

PHOTO  -  MECHANICAL  engraved  printing- 
plates  have  largely  revolutionized  pressroom 
theories,  and  owing  to  the  shallowness  of  the  en- 
graving and  to  the  greater  necessity  of  dependence 
on  the  qualities  of  paper  and  ink,  the  judgment 
and  skill  of  the  pressman  is  more  than  ever  before 
required  to  give  life  and  brilliancy  to  cut  work. 
Unevenness  in  half-tone  plates  is  a  source  of  much 
annoyance  to  the  pressman.  All  plates  should  be 
made  perfectly  level  before  etching  and  the  great- 
est uniformity  should  be  observed  in  the  grinding- 
and  polishing. 

The  following  instructions  for  preparing  half- 
tone plates  for  printing  obtains  in  one  of  the  larg-e 
establishments  of  America  noted  for  the  quality  of 
the  half-tone  work  produced.  Obtain  all  the  cuts 
on  a  certain  piece  of  work  from  the  composing 
room  before  they  are  made  up  in  the  forms,  and  of 
each  cut  have  proofs  taken  on  three  different 
weights  of  paper  —  24  by  36,  60,  70  and  80  pounds 
- — and  then  proceed  to  make  cut  underlays.  Tak- 
ing1 one  of  the  proofs  on  the  70-pound  stock,  care- 
fully trim  it  all  around,  leaving  a  margin  of  one- 
sixteenth  of  an  inch  of  blank  all  around  the  print. 


->   % 


-   ^ 


MANUAL   OF    PHOTO-ENGRAVING.  115 

Then  cut  out  of  the  sheet  all  of  the  extreme  high 
lights,  being  careful  to  cut  a  little  of  the  surround- 
ing shadows  with  them,  the  purpose  of  this  being 
to  prevent  too  much  impression  on  the  point  of 
division,  which  would  have  a  tendency  to  bring  up 
the  shallows.  Then  take  a  proof  on  the  80-pound 
stock  and  remove  from  it  the  extreme  blacks  and 
solids  —  always  cutting  a  little  inside  the  line — and 
paste  them  on  the  70-pound  sheet  already  treated, 
using  common  flour  paste  or  mucilage.  Then  take 
one  of  the  proofs  on  60-pound  stock  and  cut  out  all 
of  the  intermediate  shades  such  as  should  appear 
lighter  or  softer  in  the  finished  print.  Take  these 
several  proofs  and  paste  them  together,  and  this 
would  be  called  a  four-ply  cut  overlay,  excepting 
that  all  of  the  pieces  comprising  it  are  cut  a  trifle 
inside  of  the  line.  If  the  cut  has  more  shade  in  it 
than  can  be  properly  treated  with  three  sheets, 
take  a  50-pound  paper  in  place  of  the  60-pound  and 
add  one  sheet  to  the  underlay,  treating  it  in  the 
same  way  as  the  second  sheet  with  the  exception 
that  instead  of  cutting  out  the  extreme  solids 
remove  all  the  semi-dark  shades  as  well  and  paste 
them  on.  Having  made  the  underlays  in  the  man- 
ner described,  proceed  to  unmount  the  cuts  from 
their  bases.  In  order  to  do  this  without  injuring 
or  scratching  them  great  care  is  required.  The 
tools  which  will  be  found  to  be  the  most  advan- 
tageous are  a  small  hammer,  a  pair  of  pliers,  and  a 
small  chisel  —  this  last  should  be  about  a  quarter  of 
an  inch  in  diameter  at  the  shank  and  should  have  a 
long  tapering  blade,  and  be  about  half  an  inch 
11 


116  MANUAL   OF   PHOTO-ENGRAVING. 

wide  at  the  extremity  of  the  blade.  Some  small 
wire  brads,  such  as  are  commonly  used  for  mount- 
ing- the  plates,  a  prick  punch,  a  small  nail  set,  an 
electrotyper's  iron  finishing-  plate,  and  a  pair  of 
plate  calipers  such  as  are  used  by  electrotypers, 
are  the  other  requisites.  Having-  removed  the 
plate  from  the  block,  take  the  calipers  and  mark  at 
least  two  distinct  points  on  the  back  of  the  plate  in 
order  to  be  able  to  paste  the  underlay  accurately  in 
position.  This  done,  lay  the  cut  face  up  on  the 
iron  plate  and  with  a  small  boxwood  planer  g-o 
over  the  entire  surface,  taking-  care  to  strike  only 
a  moderate  blow.  Take  the  block  thereafter,  and 
examine  it  carefully  to  see  that  it  is  free  from 
lumps  and  rough  places  and  mount  the  cut  on  the 
opposite  side  to  that  from  which  it  was  taken  and 
send  it  to  the  composing-  room. 

This  method  saves  a  great  deal  of  time  in  the 
final  make-ready  of  the  form,  as  it  is  only  necessary 
to  even  up  the  impression  on  the  cut,  and  the  under- 
lay will  throw  the  lig-hts  and  shades  where  they 
should  be  without  any  further  care  on  the  part  of 
the  pressman,  and  for  long-  runs  will  preserve  the 
cut  much  better  than  if  a  plan  of  overlaying-  was 
followed.  It  holds  up  to  the  rollers  the  dark  parts 
of  the  cut,  properly  supplying-  them  with  ink  and 
protecting-  the  lig-hter  and  more  delicate  shades 
from  receiving-  unnecessary  pressure. 

.  The  practice  of  many  pressmen  who  obtain  g-ood 
results  is  to  even  up  the  cut  by  underlays,  and  then 
proceed  to  make  such  overlays  as  the  character  of 
the  work  will  indicate  to  be  the  most  suitable.     To 


MANUAL   OF    PHOTO-ENGRAVING.  117 

be  successful  in  making-  any  kind  of  an  overlay  as 
little  paste  as  possible  should  be  used,  only  sufficient 
to  compactly  bind  together  the  different  portions  of 
the  overlay,  and  to  register  each  piece  of  paper  over 
the  other  with  positive  accuracy.  For  work  of  dif- 
fering character  the  papers  used  in  overlays  vary. 
Impressions  of  the  cuts  are  taken,  for  instance,  on 
three  grades  of  stock  :  One  sheet,  say  of  10- 
pound  folio,  one  of  double  that  thickness  of  super- 
calendered,  and  one  sheet  of  the  stock  upon  which 
the  cut  is  to  be  printed.  Sometimes  the  last  sheet 
mentioned  is  selected  for  the  first  treatment,  which 
consists  in  cutting  away  from  it  any  large,  light 
backgrounds,  and  scraping  down  and  slitting  off 
many  of  the  light  and  medium  tones,  so  as  to  throw 
up  the  stronger  ones  and  the  solids.  A  sharp  knife 
and  some  degree  of  skill  is  necessary  to  handle  a 
sheet  of  paper  in  this  way,  but  it  is  worth  one's 
while  to  acquire  it,  for  it  saves  time  and  much  past- 
ing on  of  parts  of  overlays,  besides  giving  a  firmer 
basis. 

The  sheet  of  supercalendered  stock  may  now 
be  taken,  and  from  it  should  be  cut  all  the  light 
tints  as  well  as  some  of  the  stronger  ones.  The 
sheet  is  also  used  as  the  foundation  on  which  to 
paste  the  cut-out  portions  of  the  two  other  sheets. 

The  third  sheet  of  thin  folio  should  be  used  to 
make  overlays  for  such  portions  of  strong  solids 
and  shades  as  require  them.  These  should  be 
pasted  accurately  in  place  on  the  supercalendered 
sheet,  and  over  them  should  be  fastened  the  first 
sheet  treated.     From  this  arrangement  it  will  be 


118  MANUAL   OF    PHOTOENGRAVING. 

apparent  that  the  first  sheet,  the  folio  and  the 
supercalendered  sheets  press  on  the  form  in  the 
order  named,  and  in  their  relative  degree  of  pres- 
sures. 

WHY    PLATES    FILL    UP   WITH    PICKS. 

This  comes  from  several  causes,  usually  unsuit- 
able rollers  or  rollers  not  set  light  enough  to  prop- 
erly roll  the  delicate  plate  surfaces,  and  rollers  not 
cast  true  in  the  stocks.  Inks  that  are  too  stiff  or 
too  thin,  or  not  sufficiently  ground,  or  ground  in 
inferior  oil  or  varnish,  will  also  cause  this  trouble. 
Washing  the  plates  with  either  woolen  or  cotton 
rags  forces  into  the  sharp  openings  of  the  half-tone 
the  flock  from  the  rags,  and  this  also  causes 
"picks."  Half-tone  work  should  be  washed  with 
a  good  brush  of  medium  fineness,  and  a  clean  cot- 
ton rag  should  be  used  to  lightly  sponge  up  the 
washing  fluid  —  be  it  benzine,  astral  oil  or  turpen- 
tine. In  no  case  should  rags  alone  be  used  to  clean 
these  plates,  nor  should  anything  be  carelessly, 
harshly  or  hurriedly  rubbed  over  their  surfaces. 

Defective  coating  on  enameled  paper,  or  what  is 
known  as  surfaced  wood-cut  paper,  will  produce 
picks  and  fill-ups  on  half-tone  plates  ;  and  in  such 
cases  an  ink  with  a  very  slight  tack  should  be  used 
to  get  fair  working  results ;  but  the  form  should 
be  washed  off  oftener  than  when  better  stock  is 
running.  After  making  ready,  and  between  long 
stops,  half-tone  plates  should  be  thoroughly  cleaned 
off,  as  by  so  doing  clearer  and  more  satisfactory 
work  can  be  turned  out. 


wcr  lous  sir.  zxsvu  t 


HALF-TONE     MADE     DIRECT     FROM     BOOK    COVER. 


MANUAL   OF    PHOTO-ENGRAVING.  119 

COLORS    FOR    HALF-TONE    PRINTING.* 

In  every  child's  storehouse  are  treasured  many 
bits  of  color.  This  love  of  color,  inborn,  may 
always  be  made  of  strong-  appeal.  The  profusion 
of  illustration  constitutes  one  of  the  greatest  influ- 
ences in  every  grade  of  publication  —  commercial, 
scientific  and  literary.  The  form  and  detail  being- 
fixed  by  the  subjects  concerned,  it  remains  only  to 
print  them  in  such  quality  and  strength  of  color  as 
shall  be  best.  Since  the  greater  portion  of  print- 
ing- is  confined  to  one  color,  this  article  is  limited  to 
printing-  in  monotones. 

Fitness  to  the  subjects  themselves  controls  the 
choice  of  some  colors.  Fig-ures,  particularly  nudes, 
require  warm  tones.  It  is  not  customary,  how- 
ever, to  be  restricted  to  such  monotones  as  ap- 
proach flesh  tints.  Browns,  deep  reds  and  rich 
olives  are  all  g-ood.  Marines  are  the  most  limited 
in  rang-e  of  color,  greens  and  blues  being-  g-enerally 
used.  Landscapes  allow  more  license  in  color,  all 
of  the  autumnal  tints  being-  possibilities. 

Next  to  the  subjects,  the  purposes  and  uses  of 
the  print  must  be  reg-arded.  For  permanent  value, 
simplicity  of  effect  is  of  more  importance  than  any 
striking-  contrasts  which  will,  in  time,  prove  a 
detraction.  The  plain  catalogue  pag-e  is  made 
attractive  by  some  monotone  which  is  at  once  deco- 
rative and  an  approach  to  the  true  color  of  the 
subject.     Commercial  printing-,  such  as  catalogues 

*From  an  article  by  Mr.  Henry  Lewis  Johnson  in  The  Inland  Printer 
the  above  suggestive  notes  on  colors  for  half-tone  printing  are  taken  by 
special  permission. 


120  MANUAL   OF   PHOTO-ENGRAVING. 

and  placards,  admits  of  stronger  colors  than  are 
used  in  bound  volumes,  purely  illustrative.  The 
practical  value  of  a  catalogue  illustration  often 
requires  that  all  of  the  details  be  clearly  shown, 
and  dark  colors  are  necessary  for  this.  In  art 
catalogues  the  reverse  is  found ;  everything  is 
sacrificed  to  effect. 

Black  always  shows  the  full  strength  and  bril- 
liancy of  an  engraving.  Colors  which  approach 
black  in  density  possess  most  brilliancy  and  detail. 
Browns,  although  good,  are  open  to  some  preju- 
dice, since  for  many  years  they  have  been  used  on 
every  fine  programme,  catalogue  and  specimen 
print.  An  order  for  a  "  fancy  job"  has  been  syn- 
onymous with  brown  ink.  This  color  has  one 
practical  advantage.  Where  the  same  plates  are 
used,  year  after  year,  in  catalogues,  the}*  become 
necessarily  somewhat  worn  and  battered.  These 
defects  are  largely  obscured  by  this  neutral  color. 

Blues  are  not  much  used  in  half-tone  printing. 
In  their  use  all  of  the  lights,  which  give  contrast 
and  brilliancy  to  a  picture,  are  lost.  It  is  naturally 
a  color  seldom  used  for  landscapes.  The  slow  dry- 
ing qualities  of  the  ink  are  an  objection  to  its  use 
on  programmes  or  any  work  which  has  to  be  bound 
soon  after  printing.  Blue-black,  of  the  darkest 
shades,  is  being  largely  used,  giving  marked  bril- 
liancy to  the  print. 

Reds,  in  the  richer  carmine  shades,  are  effective 
but  somewhat  costly.  They  are  difficult  colors  to 
handle  well,  requiring  very  exact  gradations  to 
avoid   being  crude.     Yellow   has    some   important 


ZINC    ETCHING —  INTENSE    BLACK   AND    WHITE    EFFECT. 
Drawn  bv  J.  C.  Leyendecker. 


MANUAL   OF    PHOTO-ENGRAVING.  121 

uses.  Deep  corn  yellow  is  preferable  to  the  canary 
shade.  Greens  are  good  and  are  in  great  favor  at 
the  present.  Particularly  rich  effects  are  obtained 
in  deep  shades  of  olive,  yielding  strength  and 
warmth.  Such  prints  closely  approach  photograv- 
ures in  effect,  having  strength  yet  obscuring  the 
half-tone  lines.  Instead  of  primary  browns,  blues 
and  greens,  each  one  is  better  for  ordinary  pur- 
poses as  it  approaches  black. 

For  the  printer  there  is  a  practical,  and,  in- 
deed, economical  side  to  the  use  of  colored  inks. 
By  using  the  engraver's  proof  in  black  in  making 
ready,  the  print  may  be  brought  up  to  its  proper 
condition.  The  element  of  "  rush  "  usually  enters 
in  at  this  stage.  Justice  cannot  be  done  to  the  cuts 
in  black,  in  long,  hurried  runs,  as  it  is  difficult  to 
maintain  the  color.  A  slight  variation  in  the  bril- 
liancy of  the  print  in  an  olive  or  brown  does  not 
constitute  the  defect  which  it  would  in  black.  In 
place  of  strained  effects  in  descriptive  lines  and 
text,  the  monotone  is  the  desired  decoration. 

The  use  of  monotones  is  an  interesting  and  a 
critical  part  of  the  work.  For  the  simplest  print 
the  requirements  of  color  are  exacting,  and,  suc- 
cessfully handled,  constitute  a  step  in  advance  in  the 
art  of  printing. 


APPENDIX. 

TABLES   OF   WEIGHTS   AND   MEASURES 
INFORMATION   FROM   VARIOUS 
SOURCES. 


MEASURES. 

LINEAL. 

Mile. 

Rods. 

Yards. 

Feet. 

Inches. 

1     = 

320 

= 

17l 

50 

=     5280 

= 

63360 

1 

5', 
1 

=         16 

=           3 

1 

SURFACE. 

1  , 

= 

198 
36 
12 

Acre. 

Roods. 

Sq. 

Rods. 

Sq.  Yds. 

Sq.  Ft. 

1     = 

2560 

= 

io; 

2400 

=     3097600 

= 

27878400 

1 

= 

160 

=           4840 

= 

43560 

1 

VOLUME. 

30' 

1 

4         = 

272  <4 
9 

Gallon. 

Quarts 

Pints.                          Gills 

Cubic  Inches. 

:    = 

4 

= 

8 

= 

32 

= 

231 

1 

2 
1 

FLUIDS. 

16 

4 

Gallon. 

Pints. 

Ounces. 

Drams. 

Minims. 

Cubic  Centim's. 

1      = 

8       = 

128 

= 

1024       = 

61440 

=      3785435 

1       = 

16 

= 

128      = 

7 

'680 

=        473179 

1 

= 

II     II 

480 
60 

=          29574 
=            3697 

122 


APPENDIX. 

12. 

WEIGHTS. 

TROY. 

Pound. 

Ounces. 

Penn; 

1,-weij. 

fht.                 Grains. 

Grams. 

1      = 

12     = 

240 

5760         = 

373.24 

1      = 

20 

=             480         = 

31.10 

1 

=               24         = 

1.56 

APOTHECARIES'. 

Pound. 

Ounces. 

Drams 

Scruples.             Grains. 

Grains. 

1 

=     12    = 

96 

= 

288      =        5760      = 

373 . 24 

1     = 

8 

= 

24      =          480      = 

31.10 

1 

= 

3      =            60      = 

3.89 

1      =            20     — 
1      = 

1.30 
.06 

AVOIRDUPOIS. 

Pound. 

Ounces. 

Drams.                Grams. 

1      = 

16 

= 

256      =       453.60 

1 

= 

16      =         28.35 
1      =           1.77 

1  gram  =  15.43  grains   =  .03215   troy  ounces   =    .03527 

avoirdupois  ounces. 
1  grain  =  .0648  grams. 
1  pound  avoirdupois  =  lyV?  pounds  troy  =  IjVi  pounds 

apothecaries'. 
1  ounce  avoirdupois  =  lTyv  ounces  troy  =  lTv52   ounces 

apothecaries'. 
1  pound  troy  =  1  pound  apothecaries'. 

1  ounce  "      =1  ounce  " 

1  grain  "      =1  grain  " 

1  pennyweight    "      —  §  dram  " 

TO  PREPARE  PERCENTAGE  SOLUTIONS. 


For  each  fluid  ounce  of  water  take  of  the  salt  4.557  grains 
to  make  a  1  per  cent  solution,  twice  the  amount  for  a  2 
per  cent  solution,  etc. 

When  stated  in  parts  per  1,000,  etc.,  for  each  fluid  ounce 
of  water  take  of  the  salt  0.4557  to  make  1  part  in  1,000,  twice 


- 

roount  to 

I 

PR]  ::^:h   :  - 

i . 

Water 

1                                                                        ...   1  ounce 
- 

Dis-  -  the  paper 

th  soltridoi         ;   in  dark 
e.     Then 

- 
-     -    -  -    -  bleachec 

- 

^ro- 
-  7  may  be 

~ibed  in  Cbar 

- 

- '  _ ~ 

-     . 
Tar  1  .  - 

iron  123  % 

Water  .   - 

--  -  -     ■ 

- 

acid :  ri::.; 

I    gTains 
3  ounces 

5    per  cent  solution  of  ferro- 
sh  and  fix  in  10  per  cent  solution 

- 


APPENDIX.  125 


ANOTHER    PROCESS. 

Water 300  cu.  centim's 

Gelatin 10  grams 

Ferric  chloride,  in  thick  solution     20  cu.  centim's 

Tartaric  acid 10  grams 

Ferric  sulphate 10  grams 

When  paper  is  dry,  expose  under  negative  and  develop  in 

Gallic  acid 20  grams 

Alcohol 200  cu.  centim's 

Water 1  liter 

and  wash. 

VARNISHES. 
VARNISH   FOR   COLLODION   NEGATIVES. 

g    Water 30  ounces 

Borax \l/2  ounces 

White  shellac 4  ounces 

Glycerine %  ounce 

Dissolve  the  borax  in  the  water,  then  add  the  shellac  and 
warm  the  water,  keeping  it  so  until  the  shellac  is  dissolved, 
then  add  the  glycerine. 

DEAD    BLACK    VARNISH. 

Gum  lac 30  grams 

Alcohol 200  cu.  centim's 

Dissolve. 

Lampblack 60  grams 

Alcohol 40  cu.  centim's 

Dissolve  and  add  to  the  gum  solution. 


126  APPENDIX. 

PLAIN   PHOTOGRAPHIC   PAPER. 

It  is  an  easy  matter  to  prepare  one's  own  paper  and  it 
will  keep  for  any  length  of  time.  All  that  is  necessary  is 
to  use  a  good  quality  linen  paper  and  soak  it  in  a  weak  siz- 
ing of  gelatin  containing  a  chloride  salt,  so  that  when  apply- 
ing nitrate  of  silver  afterward  to  this  paper  a  chloride  of 
silver  will  be  formed.  The  following  is  an  excellent  for- 
mula: Take  a  smooth  linen  paper  if  it  is  to  be  used  for  pen- 
and-ink  work,  or  a  rough  paper  like  Whatman's  drawing 
paper  if  for  wash  work,  and  immerse  it  in  a  warm  solution 
of  the  following : 

Water 1  ounce 

Gelatin 12  grains 

Chloride  of  ammonium 8  grains 

When  the  paper  is  soaked  with  this  liquid  hang  it  up  to  dry. 
It  will  keep  indefinitely.     To  sensitize  this  paper  use  : 

Water 1  ounce 

Nitrate  of  silver 50  grains 

Nitric  acid 15  grains 

CLEARING    SOLUTION    FOR    HALF-TONE 
NEGATIVES. 

Engravers  having  trouble  with  negatives  filling  up  in 
the  intensifying  will  find  a  clearing  solution  of  great  value. 
Property  used,  it  is  one  of  the  most  valuable  aids  in  secur- 
ing perfect  half-tone  negatives.  There  are  two  ways  of 
using  this  clearing  solution.  The  first  is  to  prepare  an 
iodine  solution  : 

Iodine  in  flakes 10  grains 

Iodide  of  potassium 10  grains 

Water 1  ounce 

After  the  negative  is  intensified  with  bromide  of  copper  and 
nitrate  of  silver  as  usual,  it  should  be  examined  with  a 
magnifying  glass  to  determine  how  much  clearing  is  neces- 
sary.    Then  flow  over  the  negative  the  iodine  solution  until 


12 


APPENDIX. 

it  has  permeated  through  the  film,  wash  well,  leave  the  water 
running,  and  flow  over  the  iodized  plate  a  very  weak  solu- 
tion of  cyanide  of  potassium.  If  it  should  appear  to  clear 
the  negative  too  quickly,  thrust  the  negative  immediately 
under  the  running  water.  After  washing  examine  with  the 
glass  again,  and  proceed  or  stop  clearing  as  judgment  war- 
rants. The  majority  of  operators  add  cyanide  solution  to 
the  iodine  solution  until  the  latter  becomes  clear  as' water, 
and  use  it  then  as  the  clearing  solution. 

TWO    SUGGESTIONS   FOR   DESIGNERS. 

Wall  paper  of  neat  design  may  sometimes  be  used  as  a 
background  for  a  group  of  photographs  to  be  reproduced  in 
half-tone,  giving  a  better  appearance  than  a  plain  ground, 
and  allowing  the  time  of  an  artist  to  design  a  ground  to 
be  saved.  Good  effects  can  also  be  obtained  in  some  cases 
by  spreading  glue  over  certain  portions  of  a  design  and 
sprinkling  over  the  wet  glue  chips  of  metal  from  the  router 
or  trimmer. 

ETCHED  EMBOSSING  PLATES. 

Plates  for  embossing  can  be  made  quite  readily  by  zinc 
etching,  as  follows:  From  the  relief  plate  take  an  impres- 
sion with  black  ink  on  thin  white  paper,  as  nearly  trans- 
parent and  tough  as  can  be  obtained.  Then  dust  over  the 
wet  ink  very  finely  powdered  graphite  or  other  opaque 
powder  to  render  the  ink  still  more  impervious  to  light. 
Coat  a  thick  zinc  plate  with  the  sensitive  albumen  solution, 
place  the  paper  in  contact  with  it,  insert  in  printing  frame 
and  expose  in  same  manner  as  with  a  negative.  Then  roll 
up  and  develop  as  usual  and  the  result  will  be  an  image 
having  the  letters  or  design  of  exposed  zinc  with  a  ground 
of  transfer  ink.  The  plate  is  then  etched  in  the  usual  man- 
ner, care  being  taken  to  protect  the  edges  of  the  design 
from  breaking.  If  the  relief  plate  is  not  at  hand,  make  a 
negative  of  the  design  and  from  this  a  positive,  and  use  the 
positive  to   obtain   the   print  upon  the  zinc.     To  make  the 


128  APPENDIX. 

positive,  place  the  negative  in  the  kit  in  front  of  the  copying- 
camera,  having  the  lens  in  the  kit  inside.  Fasten  a  sheet  of 
white  paper  to  the  copy  board  and  move  the  ground  glass 
until  the  image  measures  exactly  the  proper  dimensions, 
then  proceed  as  in  making  an  ordinary  negative.  A  method 
simpler  than  the  above  would  be  to  transfer  the  image  from 
the  relief  plate  to  the  zinc  by  means  of  the  press,  paint  in 
the  ground  well  with  transfer  ink,  and  etch. 

A  SUBSTITUTE  FOR  GROUND  GLASS. 

There  is  scarcely  any  accident  more  aggravating  to  the 
photo-engraver  than  the  breaking  of  the  camera  ground 
glass.  As  it  is  of  frequent  occurrence  and  it  is  difficult  to 
obtain  glass  ground  fine  enough  for  the  purpose,  it  behooves 
the  photographer  to  be  provided  with  the  following  varnish 
which  furnishes  an  excellent  substitute  for  ground  glass: 

Sulphuric  ether 4  ounces 

Benzole 2  ounces 

Alcohol J  2  ounce 

Gum  sandarac  or  damar 100  to  150  grains 

If  too  much  alcohol  is  used  it  will  give  a  transparent 
instead  of  a  ground  glass  effect.  Flow  this  varnish  on  a 
sheet  of  plain  glass  like  collodion.  It  dries  quickly  and 
without  heat,  and  should  give  an  excellent  imitation  of 
ground  glass.  In  passing  it  might  be  said  that  if  a  little 
gl3rcerin  is  rubbed  into  the  grain  of  an  ordinary  ground 
glass  it  renders  it  much  easier  to  focus  on.  It  is  best  to  rub 
it  over  but  a  portion  of  the  ground  glass,  say  a  strip  from 
the  center  to  one  edge. 

PROVING  COLOR  PLATES. 

Mr.  J.  H.  Siedenburg,  of  New  York,  says  The  Inland 
Printer,  has  devised  the  following-  method  of  proving  color 
plates  :  In  a  worthless  piece  of  zinc,  saj-  10  by  12  in  size. 
}  -inch  holes  are  drilled  in  diagonal  corners.  Short  pieces 
of  a  steel  needle  are  driven  into  these  holes  and  soldered 


COMBINATION    OF    LINE    AND    HALF-TONE,    ETCHED 
TOGETHER    ON    ZINC. 


Qg 

he 
on 
i  11- 
th 
y. 


„  .<-        »t  ^v-  .uor- 

^vlh,\  America;  m  m  cms  country 
Mla  ton  any  British  plans  tor  the  acquisition 
of  Hawaii." 


THE  INLAND  PRINTER. 
The  April  number  of  the' Inland  Printer 
leads  off  with  a  cool  and  discriminating  re- 
view of  tne  work  of  Aubrey  Beardsley,  the 
new  eccentric  illustrator,  Mr.  Way,  the 
critic,  rightly  distinguishes  Beardsley's  work 
as  oecoratioii,  like  that  of  the  Japanese, 
rather  than  illustration.  There  are  articles 
on  "KeCKnt  Type  Designs,"  "Colored  Ink 
Fountains  for  Printing  Presses,"  "Advan- 
tage.-; of  Type  Written  Copy,"  anil  a  score  of 
other  subjects  in  which  printers  take  delight, 
besides  less  technical  studies  devoted  to  the 
aesthetic  sideof  beck-making,  and  a  profusion 
of  the  best  selected  and  most  handsomely 
printed  full-page  and  marginal  engravings. 

■po  pn^KS     RECEIVED.        " 


Ai 


c 

Bas 
tak 
bat 
Bai 
capt 

W 

east 
cone 
hous 
si  dei 

$  '  Di( 
Schc 


HALF-TONE     REPRODUCTION    OF    TYPE-MATTER. 


Appendix.  129 

there,  after  which  the  upper  ends  of  the  needles  are  filed 
to  sharp  points.  This  he  calls  the  "ground  plate."  After 
photographing-  and  etching  the  color  plates,  one  of  them 
is  taken  and  clamped  securely  to  the  center  of  the  ground 
plate  ;  ^-inch  holes  are  drilled  through  the  regular  registry 
points,  which  were,  of  course,  on  the  cop}'  and  photo- 
graphed on  each  plate.  These  holes  are  bored  through 
both  the  color  plate  and  the  ground  plate.  Now  two  block- 
ing brads  about  ^Vinch  thick  are  driven  through  the  ground 
plate  holes  from  the  back  and  cut  off  to  height  of  thickness 
of  color  plate.  With  nail  set,  punch  the  metal  around  the 
brads  to  hold  them  rigid.  When  jVinch  holes  are  bored  in 
the  center  of  the  registry  points  in  the  other  color  plates 
they  are  all  ready  for  proving.  When  the  first  color  plate  is 
proved,  the  needle  points  in  the  ground  plate  puncture  holes 
in  the  proof,  which  are  used  to  register  the  paper  in  the 
subsequent  printings,  while  the  steel  brads  keep  the  plates 
in  register. 

TO  CHANGE  THE  READING  ON  ONE  THERMOM- 
ETER SCALE  TO  THAT  ON  ANOTHER. 

Fahrenheit  to  Centigrade. —  Subtract  32  from  the  Fahren- 
heit reading  and  multiply  the  result  by  f. 

Fahrenheit  to  Reaumur. —  Subtract  32  from  Fahrenheit 
reading  and  multiply  result  by  f. 

Centigrade  to  Fahrenheit. —  Multiply  Centigrade  reading 
by  |  and  add  32  to  the  result. 

Centigrade  to  Reaumur. —  Multiply  the  Centigrade  read- 
ing by  |. 

Reaumur  to  Fahrenheit. —  Multiply  the  Reaumur  reading 
by  |  and  add  32. 

Reaumur  to  Centigrade. —  Multiply  the  Reaumur  reading 

byf. 


>00<KH>0<><><K><K>0<><HKH><><KK><>00<KH><><XK>< 


ClK  Inland  printer. 


***: 


Wbat  it  is. 


The  Inland  Printer  is  a  monthly  magazine  of 
from  ioo  to  120  pages,  9  by  12  inches  in  size,  devoted  to 
printing,  publishing,  engraving,  electrotypiug,  stereo- 
typing, bookbinding,  papermaking  and  all  the  kindred 
trades.  It  is  a  work  of  art,  and  should  be  in  the  hands 
of  every  lover  of  the  typographic  art  or  anyone  inter- 
ested in  newspaper  work  or  advertising.  Issued 
promptly  on  the  first  of  every  month.  Subscriptions 
can  begin  with  any  number. 


What  it  Contains. 


Its  pages  are  filled  with  the  most  instructive  and 
interesting  original  articles  relating  to  the  matters  that 
properly  come  within  its  domain,  besides  an  amount  of 
valuable  data,  trade  topics,  correspondence,  craft  items, 
recent  patents,  recipes,  hints  and  suggestions  that  will 
surprise  you.  In  addition  to  this,  it  is  copiously  illus- 
trated, and  the  whole  makeup  and  general  character  of 
the  work  is  such  as  to  challenge  admiration. 

ThA  Illnctt-atinnc  The  ful1  Pa&e  illustrations  and 
I  ne  IllUSirdUUn^.  those  worked  in  with  the  text  are 
all  of  a  high  order,  and  include  half-tone,  zinc  etching 
and  other  methods  of  engraving,  alike  valuable  to  the 
engraver,  process-worker,  compositor  and  pressman. 
Colored  plates,  by  various  processes,  are  also  shown. 
tl  Tpyt  Taking  up  a  copy  at  random  one  finds 
1  He  I  CM.  articles  on  proofreading,  the  point  system 
in  type  founding,  notes  on  bookbinding,  natural  colors 
in  the  printing  press,  newspapers  and  newspaper  men, 
the  country  newspaper,  typographical  make-ready,  ad- 
vertising, convention  notes,  review  of  type  designs, 
pressroom  queries  and  answers,  process  engraving,  new 
patents,  trade  notes  and  much  general  information. 
Tl>~    A -l.,«_*:„«™«„i..      These  are  as  important  in   a 

The  Advertisements.   way  as  any  other  part  of  the 

Inland  Printer,  for  the  reason  that  they  are  set  in 
attractive  and  catchy  style,  alike  beneficial  to  the  com- 
positor and  "ad."  writer,  and  printed  in  the  same  excel- 
lent way  that  the  other  part  of  the  journal  is.  This  part 
will  interest  you  as  well  as  the  text. 

SUBSCRIPTION   price: 
$2.00  per  Year  ;    $1.00  for  Six  Months  ;    20c.  per  Copy. 

No  free  copies  and  no  exchanges.  Subscribe  through 
your  type  founder,  material  dealer  or  news  agent,  or 
send  direct  to 

CDe  Inland  Printer  Companp, 


150  NASSAU  STREET, 
NEW  YORK. 


212-214  MONROE  ST. 
CHICAGO. 


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